NCM 112 Module 4 Communicable Disease PDF

CARE OF CLIENTS WITH PROBLEMS IN OXYGENATION, FLUID & ELECTROLYTES, INFECTIOUS, INFLAMMATORY & IMMUNOLOGIC RESPONSE, CELLULAR ABERRATIONS, ACUTE & CHRONIC NCM 112 LECTURE | 1st Sem | BSN 3A S.Y 2024 - 2025 MODULE 4: UNDERSTANDING AND...

CARE OF CLIENTS WITH PROBLEMS IN OXYGENATION, FLUID & ELECTROLYTES, INFECTIOUS, INFLAMMATORY & IMMUNOLOGIC RESPONSE, CELLULAR ABERRATIONS, ACUTE & CHRONIC NCM 112 LECTURE | 1st Sem | BSN 3A S.Y 2024 - 2025 MODULE 4: UNDERSTANDING AND The environments are those surroundings and conditions external to the human or animal that cause or allow disease MANAGING INFECTIOUS/COMMUNICABLE transmission; and Time accounts for incubation periods, the life expectancy of DISEASE the host or the pathogen, and duration of the course of illness or condition. COMMUNICABLE DISEASE NOTE  is a diseases caused by an infectious agent which is The Epidemiologic Triangle Model of Disease Causation is a framework used to acquired / transferred from an infected source and is explain how communicable diseases occur and spread. It consists of three transmitted to a susceptible host either thru direct contact , interconnected components: Agent, Host, and Environment. Understanding these indiret contact or direct inoculation into the skin. elements helps in identifying the factors involved in disease outbreaks and developing Communicable disease can be either infectious, ccontagious strategies for prevention and control.’ or both. The significance and impact of communicable diseases on individuals, communities, and societies are profound. Here are some key aspects of their significance and Infectious – this disease is caused by pathogenic microbial agents, impact: such as viruses,bacteria or other microorganisms. Infectious diseases can be spread in a variety of ways. Some infectious diseases spread Public Health Threat: Communicable diseases pose a significant threat to public in more than one way. Major ways include: health, as they can spread rapidly within communities and across borders. Outbreaks  direct contact with an infected person, animal, or their and epidemics can strain healthcare systems and resources. discharges Morbidity and Mortality: Communicable diseases can cause illness and death. The  direct contact with a contaminated object severity of these diseases varies, with some causing mild symptoms while others can  contaminated food and water be life-threatening. Diseases like HIV/AIDS, tuberculosis, and malaria have claimed  disease-carrying insects millions of lives. Contagious – a disease is contagious when it spreads through direct, Economic Impact: Communicable diseases can have substantial economic bodily contact with an infected person, their discharges, or an object or consequences. The costs associated with healthcare, treatment, lost productivity due to illness, and reduced economic activity during outbreaks can be substantial. These surface they have contaminated. economic losses can affect individuals, businesses, and governments. NOTE Social Disruption: During outbreaks, social disruption can occur as schools, A communicable disease, also known as an infectious or contagious businesses, and public gatherings are closed or restricted to limit the spread of disease, is an illness caused by microorganisms such as bacteria, viruses, disease. Quarantine measures and travel restrictions can disrupt daily life and have parasites, or fungi that can be spread from one person, animal, or environment social and psychological consequences. to another. These diseases are typically transmitted through various means, including direct contact, indirect contact, airborne transmission, and vector-borne Healthcare Burden: Communicable diseases can overwhelm healthcare systems. transmission. Communicable diseases can range from mild to severe and may Hospitals and clinics may be inundated with patients, leading to a shortage of have the potential to lead to outbreaks or epidemics if not controlled properly. resources and healthcare workers. This can hinder the treatment of other medical Causative Agents: Communicable diseases are caused by infectious agents, conditions. which can include bacteria (e.g., tuberculosis), viruses (e.g., influenza), parasites (e.g., malaria), or fungi (e.g., athlete's foot). Stigmatization: People with certain communicable diseases, such as HIV/AIDS, have Modes of Transmission: These diseases can be transmitted through various faced stigma and discrimination. This can prevent individuals from seeking testing, routes, including person-to-person contact, contaminated surfaces or objects, treatment, and support, which, in turn, can hinder disease control efforts. respiratory droplets, sexual contact, insect vectors (e.g., mosquitoes carrying malaria), and more. Vulnerable Populations: Vulnerable populations, including the elderly, children, pregnant women, and those with weakened immune systems, are at greater risk of Modes of Transmission: severe illness from communicable diseases. Health disparities can be exacerbated Direct transmission: Person-to-person contact (e.g., touching, during outbreaks. kissing, sexual contact). Indirect transmission: Contact with contaminated objects, surfaces, Global Health Security: Communicable diseases are a global health security or vectors (e.g., mosquitoes). concern. Cross-border transmission can lead to pandemics that affect multiple Droplet transmission: Coughing, sneezing, or talking produces countries. This highlights the need for international collaboration and information droplets that can spread diseases like the flu or COVID-19. sharing to control outbreaks. Airborne transmission: Microorganisms remain suspended in the air and can be inhaled (e.g., tuberculosis, measles). Preventable with Vaccination: Many communicable diseases are preventable Vector-borne transmission: Spread through insects or animals through vaccination. Immunization programs have successfully reduced the (e.g., malaria, dengue, Lyme disease). prevalence of diseases like polio, measles, and hepatitis B, demonstrating the potential to eliminate or control these diseases. Contagiousness: Many communicable diseases are contagious, meaning they can easily spread from an infected person to others. The level of contagiousness Research and Innovation: Communicable diseases drive research and innovation in can vary among diseases. healthcare. Efforts to understand and combat these diseases have led to Incubation Period: Communicable diseases often have an incubation period advancements in diagnostics, treatments, and vaccine development. during which an infected individual may not yet show symptoms but can still transmit the disease to others. Behavioral Changes: Outbreaks of communicable diseases often lead to changes in Symptoms: Symptoms of communicable diseases can vary widely and may public behavior, such as increased handwashing, mask-wearing, and social include fever, cough, rash, diarrhea, fatigue, and more, depending on the distancing. These behavioral changes can persist even after the outbreak subsides. specific disease. Prevention and Control: Strategies for preventing and controlling communicable diseases include vaccination, good hygiene practices (e.g., handwashing), use of protective barriers (e.g., condoms), isolation and THE AGENT/ETIOLOGIC AGENT/CAUSATIVE AGENT quarantine measures, and public health interventions.  Agents of infectious diseases include bacteria, viruses, Epidemics and Pandemics: Some communicable diseases have the potential parasites, fungi, and molds. to cause outbreaks, epidemics, or even global pandemics when they spread  A variety of factors influence whether exposure to an widely across different regions or countries. organism will result in disease, these includes: a) Pathogenicity- ability to cause disease b) virulence- potency of organism which influence course of EPIDEMIOLOGIC TRIANGLE MODEL TRIAD OF DISEASE disease CAUSATION c) Dose- the number of causative agent The agent is the cause of disease; d) Infectivity –ability to enter the body and move to tissues The host is an organism, usually a human or an animal, that e) Antigenicity – ability to stimulate antibody response harbors the disease 1| INALGAN, F. CARE OF CLIENTS WITH PROBLEMS IN OXYGENATION, FLUID & ELECTROLYTES, INFECTIOUS, INFLAMMATORY & IMMUNOLOGIC RESPONSE, CELLULAR ABERRATIONS, ACUTE & CHRONIC NCM 112 LECTURE | 1st Sem | BSN 3A S.Y 2024 – 2025 Agent  The environment includes the external factors that affect The agent is the microorganism or pathogen that causes the the agent and host interaction. This can be physical (e.g., disease. This can include bacteria, viruses, fungi, or climate, geography), biological (e.g., presence of vectors like parasites. mosquitoes), or social (e.g., crowded living conditions, Example: For malaria, the agent is the Plasmodium healthcare access). parasite; for tuberculosis, it's Mycobacterium tuberculosis.  The environment plays a role in supporting or inhibiting the The agent must be present for disease to occur, but other spread of disease. factors, such as the strength of the pathogen (virulence) and  Example: Malaria is more common in tropical environments the dose, influence whether infection occurs. where mosquitoes thrive, whereas poor ventilation can In the context of communicable diseases, an "agent" refers increase the risk of tuberculosis transmission. to the microorganism or pathogen that causes the disease.  Physical Environment: Agents are the biological entities responsible for initiating  Climate and Weather: Environmental factors like and sustaining infections in individuals. These agents can be temperature, humidity, and precipitation can influence the bacteria, viruses, parasites, or fungi, each with distinct survival and transmission of pathogens. For example, some characteristics and mechanisms of causing disease. diseases, like influenza, tend to be more common in colder, Understanding the agent responsible for a communicable drier conditions. disease is crucial for effective prevention, diagnosis,  Geography and Topography: The geographical features of treatment, and control efforts. an area, such as mountains, rivers, and forests, can impact the distribution of disease vectors and reservoirs, affecting THE HOST disease prevalence.  A host offers subsistence and lodging for a pathogen and  Vector-Borne Diseases: The environment can influence the may or may not develop the disease. habitat and breeding conditions of disease vectors such as  The level of immunity, genetic makeup, level of exposure, mosquitoes (for diseases like malaria and dengue) or ticks state of health, and overall fitness of the host can determine (for diseases like Lyme disease). Changes in environmental the effect a disease organism will have on it. conditions can impact vector populations and distribution.  The level of immunity, genetic makeup, level of exposure,  Water and Sanitation: Access to clean water and proper state of health, and overall fitness of the host can determine sanitation facilities is critical for preventing waterborne the effect a disease organism will have on it. diseases like cholera and dysentery. The environment, The host is the individual or organism that harbors the including water sources and sewage systems, plays a disease-causing agent. crucial role in disease transmission. Host factors that affect susceptibility to disease include:  Urbanization and Population Density: High population Genetics (inherited resistance or vulnerability to density in urban areas can facilitate the rapid spread of certain infections) communicable diseases. Environmental factors within cities, Immune status (immunocompromised individuals such as sanitation infrastructure and housing conditions, can are more at risk) also impact disease transmission. Age, sex, lifestyle, and pre-existing conditions  Zoonotic Diseases: which are transmitted between animals (e.g., smoking, poor nutrition). and humans, often have environmental components. Example: In HIV infection, the host is the person exposed to Changes in land use, deforestation, and human the virus. encroachment into wildlife habitats can increase the risk of In the context of communicable diseases, a "host" refers to zoonotic disease transmission. an organism (usually a human or animal) that provides an  Travel and Trade: Globalization and increased human environment for a pathogen (such as a bacteria, virus, mobility contribute to the spread of communicable diseases. parasite, or fungus) to live, grow, and potentially cause Air travel, trade, and migration can quickly transport disease. The host-pathogen interaction is a fundamental pathogens from one region to another, affecting disease aspect of communicable diseases, as it determines whether dynamics. an individual becomes infected and the outcome of the infection. THE TIME Primary Host: The primary host is the organism in which a  Time includes the severity of illness in relation to how long a pathogen naturally lives and reproduces. For many human person is infected or until the condition causes death or diseases, humans are the primary host. In such cases, the passes the threshold of danger towards recovery. pathogen has evolved to specifically infect and reproduce  Delays in time from infection to when symptoms develop, within human hosts. duration of illness, and threshold of an epidemic in a Secondary Host: In some cases, pathogens have multiple population are time elements with which the epidemiologist hosts in their life cycle. For example, a parasite might infect is concerned. a primary host (e.g., a mosquito) and then be transmitted to  In the context of communicable diseases, "time" plays a a secondary host (e.g., a human) when the mosquito bites critical role in several aspects, including the course of the secondary host. infection, disease progression, transmission dynamics, and public health response. THE ENVIRONMENT  Incubation Period: The incubation period is the time  Environmental factors can include the biological aspects between when a person is exposed to a pathogen (e.g., as well as social, cultural, and physical aspects of the through contact with an infected individual or contaminated environment. surface) and when they start showing symptoms of the  The surroundings in which a pathogen lives and the effect disease. The length of the incubation period can vary the surroundings have on it are a part of the environment. depending on the specific disease and the individual's  The environment can be within a host or external to it in the immune response. community.  Latent Period: In some diseases, there is a latent period  In the context of communicable diseases, the "environment" during which the pathogen is present in the host's body but refers to the external factors and conditions that can is not actively causing symptoms. This is commonly seen in influence the transmission and prevalence of infectious diseases like HIV, where the virus can remain latent for diseases. The environment plays a significant role in the years before symptoms appear. dynamics of communicable diseases as it can affect the  Disease Progression: The time it takes for a communicable survival and spread of pathogens, the behavior of disease disease to progress from mild symptoms to severe illness vectors, and human behaviors that impact disease can vary. Understanding this progression is important for transmission. healthcare providers to make informed decisions about treatment and care. Environment 2| INALGAN, F. CARE OF CLIENTS WITH PROBLEMS IN OXYGENATION, FLUID & ELECTROLYTES, INFECTIOUS, INFLAMMATORY & IMMUNOLOGIC RESPONSE, CELLULAR ABERRATIONS, ACUTE & CHRONIC NCM 112 LECTURE | 1st Sem | BSN 3A S.Y 2024 – 2025  Transmission Dynamics: Time is a crucial factor in chain of infection is essential for identifying points where understanding how communicable diseases spread within preventive measures can be implemented. populations. For example, the time an infected individual  Infectious Agent: This is the first link in the chain and remains contagious and capable of transmitting the disease represents the microorganism or pathogen that causes the to others is an important consideration for public health disease. Infectious agents can include bacteria, viruses, interventions. parasites, and fungi. The characteristics of the infectious  Epidemic Curve: Epidemiologists use time-based data to agent, such as its virulence and ability to survive in the create epidemic curves, which show the number of new environment, are essential factors in disease transmission. cases of a disease over time. These curves help identify  Reservoir Host or Source: The reservoir host or source is trends, estimate the rate of disease spread, and assess the the organism or environment where the infectious agent impact of control measures. naturally resides and multiplies. It may be an infected  Recovery and Immunity: The time it takes for an individual person, animal, or even an inanimate object (fomite) that to recover from a communicable disease and develop carries the agent. The reservoir host is the source from immunity against future infections varies. In some cases, which the infectious agent is ultimately transmitted to a individuals may remain immune for a lifetime, while in susceptible host. others, immunity may wane over time.  Portal of Exit: To continue the chain, the infectious agent  Public Health Response: Time is of the essence in must exit the reservoir host or source. This typically occurs responding to outbreaks and epidemics. Rapid identification through specific portals of exit, such as respiratory of cases, contact tracing, isolation of infected individuals, secretions (e.g., coughing or sneezing), blood, bodily fluids and vaccination campaigns all rely on timely actions to (e.g., saliva or urine), feces, or skin lesions. The choice of control the spread of disease. portal of exit depends on the type of infectious agent and the  Vaccine Development: The development of vaccines route of transmission. against communicable diseases involves a series of stages  Mode of Transmission: Once the infectious agent exits the and often takes years. Researchers need time to conduct reservoir host or source, it must find a way to be transmitted preclinical studies, clinical trials, and safety assessments to a new host. Modes of transmission can include: before vaccines can be approved and distributed.  Direct Contact: When the infectious agent is transferred  Seasonal Patterns: Some communicable diseases exhibit directly from an infected person or animal to a susceptible seasonal patterns, with higher transmission rates during host through physical contact. specific times of the year. Understanding these patterns is  Indirect Contact: When the agent is transmitted via essential for preparedness and response efforts. contaminated surfaces, objects, or fomites that come into  Long-Term Trends: Analyzing communicable disease data contact with susceptible hosts. over time allows public health officials to identify long-term  Airborne Transmission: When infectious agents become trends, such as changes in disease incidence, emergence of suspended in the air as respiratory droplets or dust particles drug resistance, and shifts in disease distribution and are inhaled by susceptible hosts.  Vector-Borne Transmission: When a vector (e.g., THE INFECTION CYCLE/CHAIN OF INFECTION mosquito, tick, or flea) carries and transmits the infectious  When a pathogen enters its host and multiplies inside of it, agent from one host to another. we term that process an infection. A pathogen can be  Portal of Entry: To establish an infection in a new host, the anything you can imagine, such as a virus, bacterium, infectious agent must enter through a specific portal of entry, fungus, parasite, or even a prion (an abnormally shaped such as the respiratory tract, gastrointestinal tract, skin, or protein that causes disease). When tissues /organs are mucous membranes. The choice of portal of entry depends damaged as a result of infection and the body failed to on the agent's characteristics and the mode of transmission. function normally then the client enters a Disease state.  Susceptible Host: The final link in the chain is the  The infection cycle, also known as the disease transmission susceptible host. This represents an individual who is cycle, refers to the series of events and interactions that vulnerable to the infectious agent due to factors such as lack occur in the spread of an infectious agent from one host to of immunity, compromised immune system, or other risk another. Understanding the infection cycle is vital for factors. The agent must successfully establish an infection in identifying points at which interventions can be implemented the susceptible host for the chain to continue. to prevent or control the transmission of communicable diseases.  Chain of Infection:  Agent: The microorganism that causes the disease (e.g., bacteria, virus).  Reservoir: The habitat where the agent lives (e.g., humans, animals, environment).  Portal of Exit: The way the agent leaves the reservoir (e.g., respiratory secretions, feces).  Mode of Transmission: How the agent spreads from one host to another.  Portal of Entry: The way the agent enters a new host (e.g., broken skin, respiratory tract).  Susceptible Host: A person who is vulnerable to infection (e.g., individuals with weakened immune systems).  The Infection Cycle is like a chain consisting of six links. To produce disease, each link of the infectious process must be present in a logical sequence. Removing one link in the chain will control the cycle of infection.  The "Chain of Infection" is a concept used in epidemiology and public health to describe the sequence of events that must occur for an infectious disease to spread from one THE CHAIN OF INFECTION person to another. It consists of a series of interconnected A. Etiologic Agent/ Causative Agent links or stages that, if broken or interrupted, can prevent the 1. Metazoa are multicellular animals, many of which are parasites. transmission of the infectious agent. Understanding the Examples: 3| INALGAN, F. CARE OF CLIENTS WITH PROBLEMS IN OXYGENATION, FLUID & ELECTROLYTES, INFECTIOUS, INFLAMMATORY & IMMUNOLOGIC RESPONSE, CELLULAR ABERRATIONS, ACUTE & CHRONIC NCM 112 LECTURE | 1st Sem | BSN 3A S.Y 2024 – 2025 a) Trichinella spiralis causing Trichinellosis, transmitted through 2. New larvae then penetrate the intestinal wall and travel undercooked meat. through the bloodstream to muscles, where they encyst (form cysts) and can live for years. 2. Symptoms: NOTE 1. Early: Nausea, diarrhea, abdominal pain. These organisms are characterized by their complex, multicellular 2. Later: Muscle pain, swelling, fever, and weakness as structure, as opposed to single-celled animals like protozoa. The term larvae invade muscles. "Metazoa" is used to distinguish these animals from single-celled life 3. Prevention: forms and to highlight their shared characteristics as multicellular 1. Thoroughly cook meat, especially pork, to kill larvae. organisms. 2. Freezing meat can also help destroy larvae. Reproduction: Metazoans reproduce sexually, although some may 4. Treatment: also have asexual reproduction methods. Sexual reproduction 1. Antiparasitic medications like albendazole are used to involves the fusion of specialized reproductive cells (sperm and eggs) treat trichinosis, especially in the early stages. to produce offspring. Key Characteristics of Metazoa 1. Multicellularity: Metazoans are composed of multiple cells that perform specialized functions. 2. Differentiated Tissues: Cells in metazoans are organized into tissues such as muscles, nerves, and epithelial tissues, each with specific roles. 3. Eukaryotic Cells: Like all animals, metazoans have cells with a true nucleus and membrane-bound organelles. 4. Heterotrophy: They are heterotrophs, meaning they obtain energy by consuming other organisms rather than through photosynthesis or chemosynthesis. 5. Development: Metazoans go through a developmental process, starting from a fertilized egg (zygote) that divides and differentiates into various cell types and tissues. Metazoa refers to a large and diverse kingdom of multicellular animals that are characterized by complex structures and differentiated tissues. It is a major b.) Ascariasis (caused by Ascaris lumbricoides),a disease usually branch of the animal kingdom and includes everything from simple organisms like accompanied by colicky pains and diarrhea, caused by the presence sponges to complex animals like mammals. Metazoans are distinct from unicellular organisms (Protozoa) and exhibit advanced features like specialized of ascaris in the gastrointestinal canal. tissues and organ systems. NOTE Key Characteristics of Metazoa Ascariasis is a common human parasitic infection caused by the 1. Multicellularity: Metazoans are composed of multiple cells that roundworm Ascaris lumbricoides. It is one of the most prevalent parasitic perform specialized functions. infections worldwide, particularly in regions with poor sanitation and 2. Differentiated Tissues: Cells in metazoans are organized into tissues hygiene practices. such as muscles, nerves, and epithelial tissues, each with specific Causative Agent: The causative agent of ascariasis is the nematode roles. (roundworm) Ascaris lumbricoides. These worms are pale white or pinkish 3. Eukaryotic Cells: Like all animals, metazoans have cells with a true in color and can grow up to 35 centimeters (14 inches) in length. nucleus and membrane-bound organelles. A nematode is a type of roundworm belonging to the phylum Nematoda. 4. Heterotrophy: They are heterotrophs, meaning they obtain energy by Nematodes are unsegmented, cylindrical worms with a complete consuming other organisms rather than through photosynthesis or digestive system (mouth to anus). They are one of the most diverse and chemosynthesis. abundant groups of animals on Earth, found in various environments, 5. Development: Metazoans go through a developmental process, including soil, freshwater, marine habitats, and as parasites in plants, starting from a fertilized egg (zygote) that divides and differentiates animals, and humans. into various cell types and tissues. Transmission: Ascariasis is primarily transmitted through the ingestion of Ascaris eggs present in contaminated food, water, or soil. The eggs are Classification of Metazoa passed in the feces of infected individuals and can survive in the Metazoans are divided into various phyla based on body plans, symmetry, and environment for extended periods. Infection occurs when a person organ systems. Some of the major groups include: consumes food or water contaminated with these eggs. 1. Porifera (sponges): The simplest metazoans, lacking true tissues and organs. Key Points: 2. Cnidaria (jellyfish, corals): Organisms with radial symmetry and 1. Lifecycle: specialized stinging cells (cnidocytes). 1. Eggs are ingested and hatch into larvae in the intestines. 3. Platyhelminthes (flatworms): Simple, bilaterally symmetrical animals 2. Larvae then migrate to the lungs via the bloodstream, where with no body cavity (acoelomates). they mature, are coughed up, and swallowed. 4. Arthropoda (insects, crustaceans): The largest phylum, consisting of 3. They return to the intestines as adult worms, where they live animals with exoskeletons, segmented bodies, and jointed limbs. and reproduce. 5. Mollusca (snails, octopuses): Soft-bodied animals, often with a hard 2. Symptoms: external shell. 1. Mild infections may cause no symptoms. 6. Chordata (vertebrates like fish, birds, mammals): Organisms with a 2. Heavy infections can lead to abdominal pain, malnutrition, notochord, a dorsal nerve cord, and in most cases, a vertebral column. bloating, and sometimes intestinal blockage. 3. During the lung migration phase, some may experience Human Relevance: Many metazoans, including livestock and fish, are vital for coughing, wheezing, or fever. food production, while others, like parasites (e.g., worms), can cause diseases in 3. Prevention: humans and animals. 1. Practice good hand hygiene, especially before eating and after using the bathroom. Examples of Metazoans 2. Wash fruits and vegetables thoroughly and ensure safe  Simple Metazoans: Sponges and jellyfish, which lack complex organ sanitation. systems. 4. Treatment:  Complex Metazoans: Insects, reptiles, birds, and mammals, which 1. Antiparasitic medications like albendazole or mebendazole have intricate organ systems such as circulatory, respiratory, and are effective in eliminating the worms. nervous systems. Trichinella spiralis is a parasitic roundworm that causes trichinosis (or trichinellosis) in humans and other animals. It is primarily transmitted through the consumption of undercooked or raw meat, especially pork that contains the larvae of the worm. Key Points: 1. Lifecycle: 1. After ingestion, larvae are released in the stomach, mature into adult worms in the intestines, and reproduce. 4| INALGAN, F. CARE OF CLIENTS WITH PROBLEMS IN OXYGENATION, FLUID & ELECTROLYTES, INFECTIOUS, INFLAMMATORY & IMMUNOLOGIC RESPONSE, CELLULAR ABERRATIONS, ACUTE & CHRONIC NCM 112 LECTURE | 1st Sem | BSN 3A S.Y 2024 – 2025 c. Hookworm (caused by Necator americanus) transmitted through and South America. Schistosomiasis is transmitted through contact feces-contaminated water and soil. Infestation can cause chronic with contaminated freshwater, making it a waterborne disease. anemia that often results in retarded mental and physical development The main species that cause schistosomiasis in humans are: of children. Schistosoma mansoni: Primarily found in Africa and South America. NOTE Schistosoma japonicum: Found in East Asia. Hookworms are parasitic nematode worms that infect the intestines Schistosoma haematobium: Common in Africa and the Middle of humans and other animals. There are several species of East. hookworms that can cause infections in humans, but the two most common species are Ancylostoma duodenale and Necator In the Philippines, schistosomiasis is primarily found in certain regions, americanus. particularly in areas with freshwater bodies that are conducive to the lifecycle of the schistosomiasis-causing parasites. Key areas include: Life Cycle: 1. Western Visayas: Particularly in the provinces of Iloilo, Capiz, and Infective Larvae: Hookworm larvae in the soil become infective when Aklan. they mature to a specific stage. They can penetrate the skin of 2. Central Luzon: Regions like Pampanga and Bulacan have reported humans or animals that come into contact with contaminated soil, cases. typically through bare feet or hands. 3. Mindanao: Areas such as Zamboanga Peninsula and Davao. Migration to the Lungs: Once inside the host, the larvae migrate Causative Agent: Schistosomiasis is caused by several species of through the bloodstream to the lungs. In the lungs, they move up the Schistosoma, with three main species being responsible for human respiratory tract, causing symptoms such as coughing and throat infections: Schistosoma mansoni, Schistosoma haematobium, and irritation. They are then swallowed and reach the small intestine. Schistosoma japonicum. Adult Worms: In the small intestine, the larvae mature into adult Transmission: Schistosomiasis is transmitted when people meet worms. These worms attach themselves to the intestinal wall using freshwater sources (rivers, lakes, and ponds) that are infested with hook-like mouthparts and feed on the host's blood. schistosome larvae (cercariae). The larvae penetrate the skin of Egg Production: Adult female hookworms lay eggs, which are then individuals who are exposed to contaminated water, such as when passed in the host's feces. These eggs can contaminate the soil. swimming, bathing, or wading. Continued Transmission: When people defecate in areas with poor sanitation or when human waste is used as fertilizer, the Life Cycle: contaminated soil can contain hookworm eggs. This perpetuates the Cercarial Stage: The infectious stage of the parasite is the cercaria, cycle by allowing new hosts to become infected when they come into which is released by snail hosts that have become infected with contact with the soil. schistosome larvae. Symptoms: Symptoms of hookworm infection can vary in severity Penetration of Human Skin: When individuals meet contaminated and may include: water, cercariae penetrate the skin and transform into Anemia (due to blood loss caused by the worms) schistosomulae, which enter the bloodstream. Abdominal pain Migration and Maturity: The schistosomulae migrate to the veins of Diarrhea the liver (S. mansoni and S. japonicum) or the bladder (S. Malnutrition and stunted growth (especially in children) haematobium), where they mature into adult worms. Skin rashes or itching at the site of larval penetration (often called Egg Production: Adult female worms lay eggs, which are excreted in "ground itch") the urine (S. haematobium) or feces (S. mansoni and S. japonicum) Fatigue and weakness of infected individuals. Eggs in Water: Eggs released into the environment hatch into Diagnosis: miracidia in freshwater, and miracidia infect snail intermediate hosts. Diagnosis of hookworm infection is usually based on identifying eggs Cercarial Production: Inside snails, miracidia develop into cercariae, in a stool sample. Blood tests can also detect anemia or eosinophilia which are released into the water, completing the life cycle. (an increased number of a type of white blood cell) associated with the infection. Symptoms: Symptoms of schistosomiasis can vary depending on the species of Treatment: Schistosoma and the stage of infection. Early-stage infections may Hookworm infections are treated with antiparasitic medications such be asymptomatic, but chronic infections can lead to: as albendazole or mebendazole. These medications kill the adult Abdominal pain worms and larvae, allowing the body to expel them naturally. Diarrhea Prevention: Preventing hookworm infections involves: Bloody urine (hematuria in S. haematobium infection) Improved sanitation and sewage disposal to reduce contamination of Liver enlargement and damage (hepatosplenic disease in S. soil with hookworm eggs. mansoni and S. japonicum infections) Wearing shoes or protective footwear to prevent larval penetration Bladder wall damage (in S. haematobium infection) through the skin. Malnutrition and growth impairment in children Deworming programs in endemic areas to treat and prevent Organ damage and potentially life-threatening complications in infections, especially in children. severe cases Health education to promote proper hygiene practices. Diagnosis: Diagnosis is typically made by identifying schistosome eggs in urine or stool samples or by detecting antibodies against the parasite in blood tests. Imaging studies, such as ultrasound, may be used to assess organ damage. Treatment: Schistosomiasis can be treated with specific antiparasitic drugs, such as praziquantel, which effectively kill the adult worms. Mass drug administration (MDA) programs are implemented in endemic areas to treat and control the disease. Prevention: Preventing schistosomiasis involves: Avoiding contact with contaminated freshwater. d. Schistosomiasis, caused by a blood fluke (Ex: Schistosoma Providing safe drinking water sources. japonicum, S. haematobium and S. mansoni) and transmitted through Health education on the risks of contamination. contaminated water. Symptoms are related to the number and location Snail control programs to reduce the number of infected intermediate hosts. of eggs in the human body, and may involve the liver, intestines, Regular deworming of at-risk populations. spleen, urinary tract, and reproductive system. 2. Protozoa are single-cell organisms with a well-defined nucleus. NOTE Schistosomiasis, also known as bilharzia, is a parasitic disease Some of these are human parasites. Examples of diseases cause by caused by trematode worms of the Schistosoma genus. It is a major protozoa include: neglected tropical disease (NTD) that affects millions of people in a) Malaria (caused by Plasmodium species) tropical and subtropical regions, particularly in parts of Africa, Asia, b.) Giardiasis (caused by Giardia Lamblia) 5| INALGAN, F. CARE OF CLIENTS WITH PROBLEMS IN OXYGENATION, FLUID & ELECTROLYTES, INFECTIOUS, INFLAMMATORY & IMMUNOLOGIC RESPONSE, CELLULAR ABERRATIONS, ACUTE & CHRONIC NCM 112 LECTURE | 1st Sem | BSN 3A S.Y 2024 – 2025 NOTE Sexual Reproduction: Some protozoa have the capacity for sexual Protozoa are a diverse group of single-celled microorganisms that reproduction, involving the exchange of genetic material between belong to the domain Eukaryota. They are classified in the kingdom two individuals. This process can contribute to genetic diversity. Protista, although this classification is somewhat outdated, as many Ecological Roles: protozoa are now grouped into various subgroups based on genetic Predators: Many protozoa are important predators in microbial and morphological characteristics. Protozoa can be found in various ecosystems, controlling the populations of bacteria and algae. aquatic and terrestrial environments and play important ecological Decomposers: Some protozoa contribute to the decomposition of roles, but some are also known for causing diseases in humans and organic matter, aiding in nutrient recycling. animals. Pathogenic Protozoa: Human Diseases: Several species of protozoa are known to cause Cell Structure and Characteristics: diseases in humans, including malaria (Plasmodium), amoebic Eukaryotic: Protozoa are eukaryotic organisms, which means they dysentery (Entamoeba histolytica), sleeping sickness have a true nucleus and membrane-bound organelles. (Trypanosoma), and giardiasis (Giardia lamblia), among others. Single-Celled: Most protozoa are unicellular, although some colonial forms exist. Giardiasis is an intestinal infection caused by the protozoan parasite Giardia Diversity: Protozoa exhibit a wide range of shapes, sizes, and lamblia (also known as Giardia intestinalis). It is one of the most common structures. They can be amoeboid, flagellated, ciliated, or non-motile. waterborne diseases worldwide. Habitats: Aquatic: Many protozoa inhabit freshwater and marine environments, Key Points: including lakes, rivers, oceans, and ponds. 1. Transmission: Terrestrial: Some protozoa can be found in soil and decaying organic 1. Giardiasis is typically spread through contaminated matter in terrestrial ecosystems. water, including lakes, streams, and poorly treated Symbiotic: Certain protozoa are symbiotic, meaning they live in close municipal water supplies. association with other organisms, such as in the guts of animals or in 2. It can also be transmitted through food, close contact the tissues of plants. with infected individuals, or by fecal-oral transmission. 2. Lifecycle: Key Characteristics: 1. The parasite exists in two forms: trophozoites (active 1. Cell Structure: form) and cysts (inactive, resilient form). 1. Protozoa are unicellular and have complex cellular 2. After ingestion, cysts release trophozoites in the structures, including a nucleus and organelles. intestines, where they multiply and can cause symptoms. 2. They can exhibit different shapes and sizes. 3. Symptoms: 2. Nutrition: 1. Symptoms usually appear 1 to 3 weeks after exposure 1. They can be heterotrophic (feeding on organic matter) or and may include: autotrophic (performing photosynthesis). 1. Diarrhea (often watery and foul-smelling) 2. Many protozoa engulf food through a process called 2. Abdominal cramps and bloating phagocytosis. 3. Nausea and vomiting 3. Movement: 4. Fatigue and weight loss 1. Protozoa exhibit various means of movement, including: 2. Some individuals may be asymptomatic but can still 1. Flagella: whip-like structures for swimming. spread the infection. 2. Cilia: tiny hair-like structures for locomotion Animal Diseases: Protozoa can also cause diseases in animals, and feeding. such as coccidiosis in poultry and toxoplasmosis in cats. 3. Pseudopodia: temporary extensions of the cell body for movement and capturing food. Types of Protozoa: Protozoa are classified into several groups based on their movement and structure: 1. Amoeboids: 1. Move using pseudopodia (e.g., Amoeba). 2. Flagellates: 1. Move using flagella (e.g., Trypanosoma, which causes sleeping sickness). 3. Ciliates: 1. Move using cilia (e.g., Paramecium). 4. Sporozoans: 1. Non-motile and often parasitic (e.g., Plasmodium, which AMOEBIASIS (CAUSED BY ENTAMOEBA HISTOLYTICA) causes malaria). Amoebiasis, also known as amebiasis or amoebic Medical Significance: dysentery, is a parasitic infection caused by the protozoan Protozoa can be responsible for various diseases in humans and animals, parasite Entamoeba histolytica. It is a significant global including: health concern, particularly in areas with poor sanitation and Malaria: Caused by Plasmodium species, transmitted by Anopheles limited access to clean water. mosquitoes. Amoebic Dysentery: Caused by Entamoeba histolytica, leading to NOTE severe gastrointestinal issues. Causative Agent: Amoebiasis is caused by the protozoan parasite Giardiasis: Caused by Giardia lamblia, resulting in diarrhea and Entamoeba histolytica. It is important to note that there are other abdominal pain. species of Entamoeba that are non-pathogenic and do not cause Sleeping Sickness: Caused by Trypanosoma brucei, transmitted by disease in humans. tsetse flies. Transmission: Amoebiasis is primarily transmitted through the Importance in Ecosystems: ingestion of water or food contaminated with the cysts of Entamoeba histolytica. Cysts are the dormant, resistant form of the parasite that Protozoa play a crucial role in nutrient cycling and as a food source can survive in the environment for extended periods. Person-to- for larger organisms in the food web. person transmission can also occur through the fecal-oral route. They can also help decompose organic matter, contributing to soil health. Life Cycle: Nutrition: Ingestion of Cysts: Infection begins when a person ingests food or Heterotrophic: Protozoa are generally heterotrophic, meaning they water containing the cysts of Entamoeba histolytica. obtain their nutrition by ingesting other microorganisms or organic Cyst Excystation: In the small intestine, the cysts release matter. They can be herbivores, carnivores, or omnivores. trophozoites, which are the active, motile form of the parasite. Feeding Mechanisms: Different protozoa use various methods for Trophozoite Colonization: The trophozoites colonize the large feeding, including phagocytosis (engulfing food particles), filter intestine (colon) and feed on bacteria and host tissues. feeding, and absorption. Reproduction: Tissue Invasion: In some cases, trophozoites can invade the lining of the colon, leading to tissue damage and inflammation. Asexual Reproduction: Protozoa primarily reproduce asexually by Formation of Cysts: Under certain conditions, some trophozoites can methods such as binary fission (splitting into two daughter cells), encyst and form new cysts. These cysts are excreted in the feces budding, or multiple fission (forming multiple daughter cells). and can contaminate the environment. 6| INALGAN, F. CARE OF CLIENTS WITH PROBLEMS IN OXYGENATION, FLUID & ELECTROLYTES, INFECTIOUS, INFLAMMATORY & IMMUNOLOGIC RESPONSE, CELLULAR ABERRATIONS, ACUTE & CHRONIC NCM 112 LECTURE | 1st Sem | BSN 3A S.Y 2024 – 2025 3. Mutualistic: Engaging in beneficial Symptoms: relationships with other organisms (e.g., Symptoms of amoebiasis can vary in severity, with some individuals mycorrhizal fungi with plants). remaining asymptomatic (having no symptoms). However, when 3. Reproduction: symptoms do occur, they may include: 1. Fungi can reproduce both sexually and asexually. Abdominal pain and cramping Asexual reproduction often occurs through spores, which Diarrhea, which may contain blood or mucus can spread and germinate in suitable conditions. Fatigue Weight loss 4. Types of Fungi: Fever 1. Yeasts: Unicellular fungi used in fermentation (e.g., Tenesmus (a constant feeling of needing to have a bowel Saccharomyces cerevisiae for baking and brewing). movement) 2. Molds: Multicellular fungi that grow in filaments (e.g., Abdominal tenderness Aspergillus and Penicillium). 3. Mushrooms: The fruiting bodies of certain fungi, often Complications: visible and edible (e.g., button mushrooms). In severe cases or when the infection is not treated promptly, Medical Significance: amoebiasis can lead to complications such as: Fungi can cause various human infections, particularly in Extraintestinal disease: Entamoeba histolytica can spread to other immunocompromised individuals. Common fungal infections include: organs, most commonly the liver, causing abscesses. Athlete's foot: A skin infection caused by Fulminant colitis: A rare but life-threatening condition characterized dermatophytes. by severe inflammation of the colon. Candida infections: Caused by Candida species, Perforation of the colon. leading to conditions like thrush or vaginal yeast infections. Diagnosis: Aspergillosis: A respiratory infection caused by Diagnosis is typically made by identifying Entamoeba histolytica Aspergillus species. cysts or trophozoites in stool samples or through serological tests Ecological Importance: that detect antibodies against the parasite. Imaging studies like Fungi play a crucial role in nutrient cycling by decomposing organic ultrasound or CT scans may be used to assess liver involvement. matter, recycling nutrients in ecosystems. They form symbiotic relationships with plants (mycorrhizae), aiding in Treatment: nutrient absorption. Amoebiasis can be treated with specific antiparasitic medications, Economic Importance: such as metronidazole or tinidazole, which are effective against both Fungi are used in food production (baking, brewing), the intestinal and extraintestinal forms of the parasite. pharmaceuticals (antibiotics like penicillin), and biotechnological applications (bioremediation). Prevention: Candidiasis is an infection caused by Candida, a type of yeast (fungus). The Preventing amoebiasis involves practicing good hygiene, including: most common species associated with human infections is Candida albicans. Drinking safe, clean water. Washing hands with soap and clean water, especially before eating Key Points: and after using the toilet. 1. Types of Candidiasis: Properly disposing of feces in sanitary facilities. 1. Oral Candidiasis (Thrush): White patches in the mouth Avoiding the consumption of raw or uncooked food and water in and throat. regions with a high risk of contamination. 2. Vaginal Candidiasis (Yeast Infection): Symptoms include itching, burning, and a thick, white discharge. 3. Invasive Candidiasis: A more serious condition where Candida enters the bloodstream, potentially affecting organs. 2. Causes: 1. Candidiasis can occur when there is an imbalance in the body’s normal flora, often due to factors like: 1. Antibiotic use, which can disrupt healthy bacteria. 2. Weakened immune system. 3. Diabetes or hormonal changes. 3. Symptoms: 1. Oral thrush: White lesions in the mouth, soreness. 2. Vaginal yeast infection: Itching, redness, swelling, and discharge. 3. Invasive candidiasis: Fever and chills that don’t improve 3.) Fungi are nonmotile, filamentous organisms that cause diseases with antibiotics. that can be very difficult to treat. Some examples important to public 4. Diagnosis: health are: 1. Diagnosis is often based on clinical symptoms and can  Candidiasis (caused by Candida albicans ).This fungal be confirmed by laboratory tests (e.g., cultures). infection causes lesions on the skin or mucous membranes, 5. Treatment: including “thrush” and vulvovaginitis. 1. Candidiasis is typically treated with antifungal medications such as fluconazole or nystatin. 6. Prevention: NOTE 1. Good hygiene, managing underlying conditions (like Fungi are a diverse group of eukaryotic organisms that play essential roles in diabetes), and avoiding unnecessary antibiotic use can ecosystems. They include yeasts, molds, and mushrooms. Unlike plants, fungi help prevent candidiasis. do not perform photosynthesis; instead, they obtain nutrients through absorption. Key Characteristics: 1. Cell Structure: 4.) Bacteria are single-celled organisms that lack a nucleus. They are 1. Fungi have a cell wall made primarily of chitin, which responsible for a wide range of human diseases, including: distinguishes them from plants (which have cell walls a) Tuberculosis (caused by Mycobacterium tuberculosis), a chronic made of cellulose). lung disease that is a major cause of disability and death in many parts 2. They are composed of hyphae, which are thread-like of the world. structures that form a mycelium (the main body of the b. Staphylococcal disease (caused by Staphylococcus aureus and fungus). other its other species), which can affect almost every organ system. 2. Nutrition: 1. Fungi are heterotrophic, meaning they obtain their Severity ranges from a single pustule of impetigo, through pneumonia, nutrients by breaking down organic matter. They can be: arthritis, endocarditis, etc., to sepsis and death. 1. Saprophytic: Decomposing dead organic c. Chlamydia and gonorrhea (caused by Chlamydia trachomatis and material (e.g., mold). Neisseria gonorrhea), the most widespread sexually transmitted 2. Parasitic: Feeding on living hosts, which can diseases. cause disease (e.g., athlete's foot). d. Tetanus and diphtheria (caused by Clostridum tetani and Corynebacterium diphtheriae) 7| INALGAN, F. CARE OF CLIENTS WITH PROBLEMS IN OXYGENATION, FLUID & ELECTROLYTES, INFECTIOUS, INFLAMMATORY & IMMUNOLOGIC RESPONSE, CELLULAR ABERRATIONS, ACUTE & CHRONIC NCM 112 LECTURE | 1st Sem | BSN 3A S.Y 2024 – 2025 NOTE Genetic Variation: Bacteria can also exchange genetic material through Bacteria are single-celled, prokaryotic microorganisms that are among the most horizontal gene transfer mechanisms, such as conjugation, transformation, and abundant and diverse forms of life on Earth. They play crucial roles in various transduction, which contribute to genetic diversity. ecosystems, including human health. Ecological Roles: Key Characteristics: Decomposers: Bacteria are essential decomposers in ecosystems, breaking 1. Cell Structure: down dead organic matter and recycling nutrients back into the environment. 1. Bacteria lack a nucleus and other membrane-bound Nitrogen Fixation: Certain bacteria, like rhizobia, can form symbiotic organelles. Their genetic material is contained in a single, relationships with plants and convert atmospheric nitrogen into a form that circular DNA molecule. plants can use, aiding in nitrogen cycling. 2. They have a cell wall, which provides structure and Bioremediation: Bacteria are used in bioremediation to clean up protection; the composition varies between different environmental pollutants and contaminants through their metabolic activities. bacterial groups (e.g., peptidoglycan in most). 2. Shapes: Pathogenic Bacteria: 1. Bacteria come in various shapes, including: Human Diseases: Some bacteria can cause diseases in humans and animals. 1. Cocci: spherical (e.g., Staphylococcus). Examples include Streptococcus (causing strep throat), Staphylococcus 2. Bacilli: rod-shaped (e.g., Escherichia coli). (causing skin infections), Escherichia coli (causing food poisoning), and 3. Spirilla: spiral-shaped (e.g., Spirillum). Mycobacterium tuberculosis (causing tuberculosis). 3. Reproduction: Plant and Animal Diseases: Bacterial pathogens can also infect plants and 1. Bacteria primarily reproduce asexually through binary animals, causing diseases that affect agriculture and ecosystems. fission, where a single cell divides into two identical cells. 4. Metabolism: 1. Bacteria can be classified based on their metabolic RICKETTSIA processes: 1. Aerobic: Require oxygen.  are a genus of bacteria usually found in the cells of lice, 2. Anaerobic: Can live without oxygen. ticks, fleas and mites. They are smaller than most bacteria 3. Facultative anaerobes: Can use oxygen but and share some characteristics of viruses. Diseases cause can also grow without it. by rickettsia include: 5. Role in Ecosystems:  Rocky Mountain Spotted-Fever (caused by Rickettsia 1. Bacteria are essential for nutrient cycling, decomposing organic matter, and fixing nitrogen in soil. rickettsii.), a tick-borne systemic disease that can be hard to 2. They can also form symbiotic relationships with other diagnose and that leads to death in 3-5% of US cases. organisms, including humans.  Typhus fever (caused by Rickettsia typhi or Rickettsia prowazekii), a louse-borne rash illness with a high case- Medical Significance: fatality rate that has occurred historically in poor living 1. Pathogenic Bacteria: conditions brought on by war and famine. 1. Some bacteria are harmful and can cause diseases, such as: 1. Streptococcus (strep throat). NOTE 2. Escherichia coli (foodborne illness). Rickettsia is a genus of small, gram-negative bacteria that are obligate intracellular 3. Mycobacterium tuberculosis (tuberculosis). parasites. They are primarily transmitted to humans through arthropod vectors, such 2. Beneficial Bacteria: as ticks, fleas, and lice. 1. Many bacteria are beneficial, playing a role in digestion Key Characteristics: (gut flora), producing vitamins, and contributing to the 1. Structure: immune system. 1. Rickettsia are similar to both bacteria and viruses in that they 3. Antibiotics: are small and can only reproduce inside host cells. 1. Antibiotics are used to treat bacterial infections, but 2. They have a cell wall but lack many features typical of free- resistance to these drugs is a growing concern. living bacteria, making them dependent on host cells for survival. Applications: 2. Transmission: 1. Biotechnology: 1. Rickettsia is usually transmitted through bites from infected 1. Bacteria are used in various applications, including genetic arthropods. Common diseases caused by Rickettsia include: 1. Rocky Mountain spotted fever (transmitted by engineering, fermentation (e.g., yogurt, cheese), and bioremediation (cleaning up environmental contaminants). ticks). 2. Research: 2. Typhus fever (transmitted by lice and fleas). 1. Bacteria are model organisms in research, particularly in 3. Rickettsialpox (transmitted by mites). 3. Pathogenicity: genetics and molecular biology, due to their simplicity and rapid growth. 1. Once inside the host, Rickettsia can invade endothelial cells Overall, bacteria are incredibly diverse and play vital roles in health, disease, and lining blood vessels, leading to symptoms such as fever, rash, ecological processes. and in severe cases, organ damage. 4. Symptoms: 1. Common symptoms of rickettsial infections include: 1. Fever and chills. 2. Rash (often spotted). 3. Headaches and muscle aches. 4. Severe cases can lead to complications such as kidney failure or septic shock. 5. Diagnosis: 1. Diagnosis often relies on clinical symptoms and can be confirmed through serological tests, PCR, or skin biopsies. 6. Treatment: 1. Rickettsial infections are typically treated with antibiotics, such as doxycycline. 7. Prevention:  Preventive measures focus on avoiding exposure to arthropod vectors, such as using insect repellent, wearing protective clothing, and taking measures to reduce tick populations in areas where they are common. Rickettsia represents an important group of pathogens that can cause significant disease, particularly in rural and wilderness areas where exposure to vectors is more NOTE likely. Reproduction: Asexual Reproduction: Bacteria reproduce asexually through a process called binary fission, where one cell divides into two genetically identical daughter cells. This process is rapid and can result in exponential population growth. 8| INALGAN, F. CARE OF CLIENTS WITH PROBLEMS IN OXYGENATION, FLUID & ELECTROLYTES, INFECTIOUS, INFLAMMATORY & IMMUNOLOGIC RESPONSE, CELLULAR ABERRATIONS, ACUTE & CHRONIC NCM 112 LECTURE | 1st Sem | BSN 3A S.Y 2024 – 2025 molecular techniques such as polymerase chain reaction (PCR) to detect the presence of Rickettsia DNA. Treatment: Rickettsial infections are typically treated with antibiotics, such as doxycycline or tetracycline, which are effective against these intracellular bacteria. Early diagnosis and prompt treatment are important to prevent severe complications. Prevention: Preventing rickettsial infections involves: Reducing exposure to arthropod vectors (e.g., using insect repellent and wearing protective clothing). Checking for and removing ticks after outdoor activities. Rocky Mountain Spotted-Fever: Caused by Rickettsia rickettsii, this Maintaining good hygiene and sanitation to prevent lice and flea disease is characterized by fever, rash, and can be severe if not infestations in crowded settings. treated promptly. It is transmitted primarily by ticks. Rocky Mountain spotted fever (RMSF) is a serious bacterial infection caused by the bacterium Rickettsia rickettsii, primarily 6. Viruses are very small, consisting of an RNA or DNA core and an transmitted through tick bites. outer coat of protein. They can reproduce and grow only inside of living cells. Many viral illnesses are significant to public health, Key Points: including: 1. Transmission: a. Influenza, a respiratory illness that contributes to development of 1. RMSF is primarily spread by dog ticks pneumonia and occurs in annual epidemics during the winter months (Dermacentor variabilis) and wood ticks b. HIV (human immunodeficiency virus), that causes Acquired (Dermacentor andersoni). Immunodeficiency Syndrome (AIDS). This severe, life-threatening 2. Infected ticks can transmit the bacteria after being pandemic disease has spread worldwide within the past 20-30 years. attached to a host for several hours. c. Rabies that is spread to humans from animal bites or scratches. 2. Symptoms: Rabies is almost always fatal in humans but is preventable by a 1. Symptoms typically appear 2 to 14 days after a vaccine. tick bite and can include: d. Measles, mumps, rubella, and poliomyelitis are all well controlled in 1. Fever and chills. the US through immunization. 2. Severe headache. 3. Muscle aches. NOTE 4. Nausea and vomiting. Viruses are microscopic infectious agents that are not classified as living 5. Rash (which usually appears a few days organisms because they lack the characteristics of life, such as the ability after fever onset and can start at the to carry out metabolic processes or reproduce independently. Instead, wrists and ankles, spreading to the viruses are considered biological entities that exist in a gray area trunk). between living and non-living matter. Structure: 3. Diagnosis: Genetic Material: Viruses contain genetic material, which can be either 1. Diagnosis is often based on clinical symptoms, DNA or RNA. This genetic material carries the instructions for virus history of tick exposure, and laboratory tests (such replication. as serology or PCR) to detect Rickettsia. Protein Coat (Capsid): Viruses are surrounded by a protein coat called a 4. Treatment: capsid. The capsid provides protection to the genetic material and helps 1. RMSF is treated with antibiotics, typically the virus attach to and enter host cells. doxycycline, which is most effective when started Envelopes: Some viruses have an outer lipid envelope derived from the host cell membrane. This envelope can play a role in viral entry into host early. cells. 5. Complications: Reproduction: 1. If left untreated, RMSF can lead to severe Obligate Intracellular Parasites: Viruses cannot reproduce or carry out complications, including organ failure, respiratory metabolic processes independently. They must infect a host cell to distress, and death. replicate. 6. Prevention: Attachment and Entry: Viruses attach to specific receptors on the surface 1. Preventive measures include avoiding tick- of host cells and enter the cells. The method of entry varies among different viruses. infested areas, using insect repellents, wearing Replication: Once inside a host cell, the virus's genetic material is protective clothing, and conducting tick checks replicated, and new virus particles are assembled. after outdoor activities. RMSF is a potentially life-threatening illness, but with prompt diagnosis and treatment, most people recover fully. Awareness and prevention VIRUSES strategies are key to reducing the risk of infection. NOTE Summary: Ticks are the vectors that can transmit various diseases, including Lyme disease. Lyme disease is a specific illness caused by a bacterium transmitted through the bite of infected ticks. Typhus: Several forms of typhus are caused by different species of Rickettsia, including Epidemic Typhus (Rickettsia prowazekii), Murine Typhus (Rickettsia typhi), and Scrub Typhus (Orientia tsutsugamushi). These diseases are characterized by fever, rash, and other symptoms and are often associated with overcrowded and unsanitary conditions. Spotted Fever Group Rickettsioses: This group includes various diseases caused by different Rickettsia species. Symptoms can include fever, rash, and other flu-like symptoms. Transmission is primarily through ticks. Release: New virus particles are released from the host cell, often Pathogenesis: Rickettsia bacteria invade endothelial cells (cells lining destroying the cell in the process. This release can occur through cell blood vessels) and reproduce within them, leading to vascular damage and lysis (cell bursting) or budding (where the virus pushes through the inflammation. This can result in the characteristic symptoms of rickettsioses, host cell membrane). including rashes, fever, and systemic effects. Diagnosis: Diagnosis of rickettsial infect