Fungi, Parasites, and Diseases PDF

FUNGI, PARASITES AND DISEASES Chippewa Valley Technical College (CVTC)  EUKARYOTIC PARASITES ▪ Eukaryotic parasites are organisms that belong to the Domain Eukarya and live in or on a host organism, deriving nutrients from the host while potentially causing harm. ▪ Unlike prokaryotic paras...

FUNGI, PARASITES AND DISEASES Chippewa Valley Technical College (CVTC)  EUKARYOTIC PARASITES ▪ Eukaryotic parasites are organisms that belong to the Domain Eukarya and live in or on a host organism, deriving nutrients from the host while potentially causing harm. ▪ Unlike prokaryotic parasites, which lack a true nucleus and other membrane-bound organelles, eukaryotic parasites are more complex cells with a defined nucleus and membrane-bound organelles.  EUKARYOTIC PARASITES ▪ These parasites can infect various host organisms, including humans, animals, and plants. Examples of eukaryotic parasites include protozoa, helminths (worms), and some fungi. ▪ Eukaryotic parasites often have complex life cycles involving different stages and may be transmitted through various mechanisms, such as vectors (e.g., mosquitoes or ticks) or contaminated food and water.  CHARACTERISTICS OF FUNGI ▪ Fungi are a diverse group of organisms with unique characteristics that distinguish them from plants, animals, and bacteria. Here are some key characteristics of fungi: 1. Eukaryotic Cells: Fungi are eukaryotes, meaning their cells have a true nucleus and membrane-bound organelles. 2. Cell Wall: Fungal cells have a rigid cell wall made of chitin, a complex polysaccharide. 3. Heterotrophic Nutrition: Fungi are heterotrophs, meaning they obtain their nutrients by absorbing organic compounds from their environment. They are mainly decomposers, breaking down complex organic matter into simpler compounds.  CHARACTERISTICS OF FUNGI 4. Hyphal Structure: Most fungi have a filamentous structure called hyphae, which form a network called mycelium. The mycelium is the main body of the fungus and is involved in nutrient absorption. 5. Saprophytic or Parasitic: Fungi can be saprophytic, obtaining nutrients from dead or decaying organic matter, or parasitic, obtaining nutrients from a living host organism.  CHARACTERISTICS OF FUNGI 6. Reproduction: Fungi reproduce both sexually and asexually. Asexual reproduction can occur through the production of spores, while sexual reproduction involves the fusion of specialized reproductive cells (gametes) or the fusion of hyphae. 7. Spore Formation: Fungi reproduce via microscopic spores, which can be dispersed by air, water, or other means. Spores are resistant structures that allow fungi to survive harsh environmental conditions. FIGURE 5.25 ▪ Multicellular fungi (molds) form hyphae, which may be septate or nonseptate. Unicellular fungi (yeasts) cells form pseudohyphae from individual yeast cells.  CHARACTERISTICS OF FUNGI 8. Lack of Chlorophyll: Unlike plants, fungi do not contain chlorophyll and cannot photosynthesize. They rely on external sources of organic matter for energy. 9. Ecological Roles: Fungi play crucial roles in ecosystems as decomposers, breaking down dead organic matter and recycling nutrients. Some fungi form mutualistic relationships with plants (mycorrhizae), aiding in nutrient uptake. 10. Diversity: Fungi exhibit incredible diversity, with an estimated 2.2 to 3.8 million species. This diversity includes molds, yeasts, mushrooms, and other forms.  CHARACTERISTICS OF FUNGI 11. Habitats: Fungi can thrive in various environments, including soil, water, and as symbionts with plants or animals. Some fungi can even survive extreme conditions, such as high temperatures or low pH. 12. Economic Importance: Fungi have both positive and negative impacts on human activities. They are used in the production of food and beverages (e.g., bread, beer), antibiotics, and enzymes. However, some fungi are also pathogens that can cause diseases in plants, animals, and humans.  CHARACTERISTICS OF PROTISTS ▪ Protists are a diverse group of eukaryotic microorganisms that do not fit into the categories of plants, animals, or fungi. As such, they exhibit a wide range of characteristics. It's important to note that protists are a paraphyletic group, meaning they do not share a common evolutionary ancestor, so their characteristics can vary significantly. However, some general characteristics of protists include: 1. Eukaryotic Cells: 1. Protists are composed of eukaryotic cells, meaning their cells have a true nucleus and membrane-bound organelles.  CHARACTERISTICS OF PROTISTS 2. Diversity: 1. Protists are highly diverse and can be unicellular, colonial, or multicellular. Some are microscopic, while others can be macroscopic. 3. Lack of Tissue Differentiation: 1. Unlike plants and animals, protists generally lack specialized tissues and organs. 4. Motility: 1. Many protists are capable of movement. Some use flagella, cilia, or pseudopodia for locomotion.  CHARACTERISTICS OF 5. PROTISTS Reproduction: 1. Protists reproduce both sexually and asexually. Asexual reproduction often occurs through binary fission, multiple fission, or budding. 6. Heterotrophic and Autotrophic Nutrition: 1. Protists can be heterotrophic (obtaining nutrients from other organisms) or autotrophic (producing their own food through photosynthesis). 7. Phagocytosis: 1. Some protists capture food particles by engulfing them through a process called phagocytosis. 8. Habitat: 1. Protists are found in diverse habitats, including freshwater, marine environments, soil, and as symbionts in the bodies of other organisms.  CHARACTERISTICS OF PROTISTS 9. Cell Wall Composition: 1. The cell walls of protists vary in composition. Some have cellulose-based cell walls, while others may have silica, chitin, or other materials. 10. Ecological Roles: 1. Protists play crucial roles in various ecosystems as primary producers, decomposers, and as part of the food web. 11. Parasitism: 1. Some protists are parasitic, causing diseases in plants, animals, and humans. 12. Plastids: 1. Some protists contain plastids, which are membrane-bound organelles involved in photosynthesis. The presence of plastids can help distinguish between different groups of protists.  CHARACTERISTICS OF HELMINTHS ▪ Helminths are parasitic worms that belong to the phylum Platyhelminthes (flatworms) or Nematoda (roundworms). These organisms can infect humans and other animals, causing various diseases. Here are some general characteristics of helminths: 1. Multicellularity: Helminths are multicellular organisms, unlike many other parasites such as bacteria or protozoa.  CHARACTERISTICS OF HELMINTHS 2. Eukaryotic Cells: Their cells have a true nucleus and other membrane-bound organelles, distinguishing them from prokaryotic organisms. 3. Bilateral Symmetry: Many helminths exhibit bilateral symmetry, meaning their bodies can be divided into two similar halves. 4. Tissues and Organs: Helminths have specialized tissues and organs, allowing them to perform specific functions within their complex bodies.  CHARACTERISTICS OF HELMINTHS 5. Digestive System: Helminths may possess a simple digestive system with a mouth and sometimes an anus. Some absorb nutrients directly through their body surface. 6. Reproductive System: Helminths have complex reproductive systems. They can reproduce sexually or asexually, depending on the species. 7. Life Cycle: Helminths often have complex life cycles involving different stages, such as eggs, larvae, and adult forms. These stages may occur in different hosts, and transmission can be direct or involve intermediate hosts. 8. Hermaphroditic or Dioecious: Some helminths are hermaphroditic, meaning an individual has both male and female reproductive organs, while others are dioecious, with separate male and female individuals.  CHARACTERISTICS OF HELMINTHS 9. External Cuticle: Nematodes (roundworms) are characterized by a tough, external cuticle that provides support and protection. 10. Parasitism: Most helminths are parasitic, meaning they live in or on a host organism and derive nutrients at the host's expense. 11. Host Specificity: Helminths often exhibit host specificity, meaning they are adapted to live in specific host species. 12. Medical Importance: Some helminths are of medical importance as they can cause diseases in humans, such as intestinal worms, filarial worms, and liver flukes. FUNGAL DISEASES  TINEA PEDIS (ATHLETE’S FOOT) Pathogen Trichophyton Signs Itching, burning and stinging sensations between the toes, Redness and scaling Symptoms on soles of the feet, Blisters, Ulcers, Cracking and peeling of skin especially around the toenails Transmission Person to person (direct contact), Contaminated surfaces (floors, towels, shoes), Warm and moist environments (public showers, swimming pools, change rooms) Diagnosis Clinical exam (skin), Microscopic examination (scrapings), Fungal culture Treatment Topical antifungal medications (Clotrimazole, Miconazole, or Terbinafine), Oral antifungal medications in severe or persistent cases (Terbinafine, Itraconazole, or Fluconazole) Prevention Keep feet clean and dry, Use antifungal powders or creams, Wear breathable footwear, Change socks regularly, Avoid walking barefoot, Rotate shoes, Treat infected pets FIGURE 5.2 ▪ Ringworm presents as a raised ring, which is gray or brown on brown or black skin (a), and red on lighter skin (b). (Credit: Centers for Disease Control and Prevention)  CANDIDIASIS (YEAST INFECTION) Pathogen Candida spp. (Candida albicans - most common) Signs Oral thrush – white creamy lesions on tongue and inner cheeks Symptoms Genital yeast infection – itching, burning, redness and abnormal genital discharge Cutaneous candidiasis – red, itchy rash in skin folds Transmission Overgrowth of Candida due to weakened immune system, antibiotic use, diabetes, pregnancy, immunosuppressive drugs Diagnosis Clinical examination and history, Microscopic exam, Culture, Blood tests Treatment Antifungal medications (Fluconazole, Clotrimazole or Nystatin) Prevention Good hygiene, Limit antibiotic use, Manage underlying conditions, Immune support, Avoid unnecessary corticosteroids  ASPERGILLOSIS Pathogen Aspergillus spp. (Aspergillus fumigatus – most common) Signs and Allergic bronchopulmonary aspergillosis – asthma like symptoms, Symptoms coughing, wheezing, fever, fatigue Invasive aspergillosis – fever, chest pain, cough, shortness of breath, blood in sputum, headache, confusion Aspergilloma – often asymptomatic, cough, hemoptysis, chest pain Transmission Inhalation of airborne spores Diagnosis Clinical evaluation (symptoms, medical history), Chest X-rays, Microscopic examination, Culture, Serology testing Treatment Antifungal medications (Voriconazole, Amphotericin B, Posaconazole, Itraconazole), Prevention Clean dry environment, Air filtration system, Precautions to avoid high risk exposure, Antifungal meds for high-risk groups prophylactically  HISTOPLASMOSIS Pathogen Histoplasma capsulatum Signs and Asymptomatic, Mild cases (fever, cough, fatigue, muscle aches), Symptoms Severe cases (respiratory distress, chest pain, fever) Transmission Bird droppings (soil), Bat droppings (soil), Inhalation of airborne spores Diagnosis Clinical evaluation (symptoms, medical history), Culture, Microscopy, Antigen testing Treatment Antifungal medications (Itraconazole), Severe cases (Amphotericin B followed by oral azole meds), Supportive care (oxygen therapy, IV fluids) Prevention Avoid bird roosting sites and caves, Wear masks (respirators) when working in environments where exposure is likely, Control bird and bat populations, Antifungal prophylaxis (weakened immune systems)  CRYPTOCOCCOSIS Pathogen Cryptococcus neoformans Signs and Pulmonary cryptococcosis – mild respiratory symptoms, cough, Symptoms shortness of breath, chest pain CNS cryptococcosis – headache, fever, nausea, vomiting, changes in mental status, seizures Transmission Inhalation of basidiospores, Bird droppings (soil) Diagnosis Antigen testing (CSF, blood, other body fluids), Culture, Chest X-ray, CT, MRI Treatment Amphotericin B and Flucytosine followed by Fluconazole, Hospitalization and supportive care Prevention Avoid environments with bird droppings, Antiretroviral therapy (HIV individuals), Prophylaxis for high-risk individuals, Education  PNEUMOCYSTIS PNEUMONIA (PCP) Pathogen Pneumocystis jirovecii Signs and Fever, Dry cough, Shortness of breath, Chest pain during Symptoms breathing, Fatigue, Weight loss Transmission Inhalation of airborne cysts of the organism possibly Diagnosis Clinical evaluation (symptoms, medical history), Chest X-ray, CT, Microscopic examination of sputum or bronchoalveolar lavage, Immunological testing, Molecular testing Treatment TMP-SMX, Pentamidine, Dapsone + Trimethoprim, Atovaquone, or Clindamycin + Primaquine Prevention Prophylaxis, ART (HIV individuals), Respiratory precautions PROTIST DISEASES  MALARIA Pathogen Plasmodium falciparum, Plasmodium vivax Signs and Episodic attacks of shivering, fever and sweating last 6 to 10 hours, Symptoms Accompanied by headaches, body aches, fatigue, nausea and vomiting; Complicated cases (anemia, hypotension, hypoglycemia, acidosis, kidney failure, acute respiratory distress syndrome, brain infections) Transmission Bites of infected Anopheles mosquitoes Diagnosis Symptoms, Microscopic observation of parasite in blood Treatment Chloroquinine, Quinine, and/or Artemisinin-based drugs, Usually combination therapies to due increasing drug resistance in Plasmodium spp. Prevention Mosquito abatement (pesticides, repellents, bed nets), Oral prophylaxis (Doxycycline), Vaccine available but being investigated  FIGURE 5.1 ▪ Malaria is a disease caused by a eukaryotic parasite transmitted to humans by mosquitos. Micrographs (left and center) show a sporozoite life stage, trophozoites, and a schizont in a blood smear. ▪ On the right is depicted a primary defense against mosquito-borne illnesses like malaria—mosquito netting. (credit left: modification of work by Ute Frevert; credit middle: modification of work by Centers for Disease Control and Prevention; credit right: modification of work by Tjeerd Wiersma)  TOXOPLASMOSIS Pathogen Toxoplasma gondii Signs and Asymptomatic, Mild flu-like symptoms Symptoms Congenital toxoplasmosis – miscarriage, stillbirth or neurological problems Immunocompromised patients – fever, headache, confusion, seizures, psychological symptoms Transmission Foodborne from undercooked meat containing T. gondii cysts; Cat feces exposure; Mother to child Diagnosis ELISA, Serological tests, PCR Treatment Pyrimethamine, Sulfadiazine Prevention Careful handling and complete cooking of meat, Avoiding untreated drinking water, Changing cat litter often, Avoiding cat litter if pregnant or immunocompromised  GIARDIASIS Pathogen Giardia lamblia Signs and Diarrhea, Gas, Abdominal cramps, Nausea, Vomiting, Chronic Symptoms infections can cause nutrient malabsorption Transmission Fecal-oral route, Contaminated fomites, Direct contact with infected patient, Ingestion of 10 cysts to establish infection Diagnosis Microscopic evaluation of feces (cysts or trophozoites), Molecular methods Treatment Supportive therapy, Metronidazole or Nitazoxanide for severe infections Prevention Boiling water to deactivate cysts, Filter water to remove cysts  FIGURE 5.3 (a) A scanning electron micrograph shows many Giardia parasites in the trophozoite, or feeding stage, in a gerbil intestine. (b) An individual trophozoite of G. lamblia, visualized here in a scanning electron micrograph. This waterborne protist causes severe diarrhea when ingested. (credit a, b: modification of work by Centers for Disease Control and Prevention)  AMEBIASIS (AMEBIC DYSENTERY) Pathogen Entamoeba histolytica Signs and Profuse diarrhea containing mucus and blood, Severe abdominal Symptoms cramping, Low grade fever, Invasive disease may cause ulcers, abscesses in the liver, lungs and the brain (rarely) Transmission Fecal-oral route, Direct contact, Contaminated fomites Diagnosis Microscopic evaluation of feces (cysts or trophozoites) Treatment Metronidazole followed by Paromomycin Prevention Avoid untreated water and ice, Boiling water deactivates cysts, Filtering removes them  AFRICAN SLEEPING SICKNESS Pathogen Trypanosoma brucei gambiense (chronic form found in West and Central Africa) Trypanosoma brucei rhodesiense (acute form in East and Southern Africa) Signs and First stage – fever, headache, joint and muscle aches, enlarged lymph nodes, itching and skin Symptoms lesions; Second stage – sleep disturbances, disturbances of sleep-wake cycle, mental confusion, severe headaches, tremors, weakness, ataxia Transmission Bite of infected tsetse flies (Glossina) Diagnosis Microscopic examination for parasites, Serological testing (antibodies), PCR Treatment First stage – T.b.gambiense (Pentamidine or Suramin); T.b.rhodesiense (Suramin or Pentamidine); Second stage – T.b.gambiense (Eflornithine or Combination of Nifurtimox and Eflornithine); T.b.rhodesiense (Suramin, Melarsoprol or Combination of Nifurtimox and Eflornithine) Prevention Insecticide-treated bed nets, Insect repellent, Long-sleeved clothing, Animal reservoir control, Active screening and treatment of infected individuals, Community education FIGURE 5.18 ▪ Trypanosoma brucei, the causative agent of African trypanosomiasis, spends part of its life cycle in the tsetse fly and part in humans. (credit “illustration”: modification of work by Centers for Disease Control and Prevention; credit “photo”: DPDx/Centers for Disease Control and Prevention)  CHAGAS DISEASE Pathogen Trypanosoma cruzi Signs and Acute Phase – fever, fatigue, body aches, headache, swelling at Symptoms infection site, enlargement of liver or spleen, swollen glands Chronic Phase – enlarged heart, enlarged esophagus or colon, difficulty swallowing, abdominal pain Transmission Feces of infected triatome (“kissing”) bugs via broken skin, mucosal membranes or ingestion of contaminated food, Congenital transmission, Blood transfusion, Lab accidents, Accidental exposure Diagnosis Blood smear identification, PCR, ELISA, Indirect immunofluorescence Treatment Benznidazole, Nifurtimox Prevention Reduce presence of triatomine bugs, Screen blood donors to prevent transmission through blood transfusions, Treat infected pregnant women, Avoid consumption of uncooked or undercooked foods, Prevent contact with infected bugs feces  CRYPTOSPORIDIOSIS Pathogen Cryptosporidium parvum, Cryptosporidium hominis Signs and Diarrhea, Nausea, Vomiting, Fever, Stomach cramps Symptoms Transmission Fecal-oral, Direct contact, Contaminated fomites Diagnosis Microscopic evaluation of stool (oocysts), Antigen detection Treatment Self-limiting, Nitazoxanide (more severe cases) Prevention Avoiding untreated water and ice, Water filters remove oocysts, Boiling deactivates oocysts Pathogen LEISHMANIASIS Leishmania donovani, Leishmania tropica, Leishmania braziliensis Signs and Cutaneous Leishmaniasis – skin sores, papules, ulcers with raised borders Symptoms Visceral Leishmaniasis (Kala-azar) – prolonged fever, weight loss, enlarged spleen and liver, anemia, weakness Mucocutaneous Leishmaniasis – ulcerative skin lesions, destruction of mucous membranes of the nose, mouth and throat Transmission Bite of infected sandflies (Phlebotomus species in the Old World and Lutzomyia species in the New World) Diagnosis Clinical examination of skin lesions, Giemsa stain, Culture, Serology testing (antibodies), PCR Treatment Antimonials (Sodium stibogluconate, Meglumine antimoniate), Amphotericin B, Miltefosine Prevention Use of insecticide-treated bed nets, Insecticides, Long-sleeved clothing, Insect repellent, Avoid outdoor activities during peak sandfly activity times, Reduce attractiveness of human dwellings to sandflies, Treat infected individuals reduce reservoir of infection HELMINTH DISEASES  ASCARIASIS Pathogen Ascaris lumbricoides Signs and Asymptomatic, Mild infection (abdominal pain, nausea, diarrhea Symptoms or blood stools); High worm load (aforementioned symptoms plus fatigue, vomiting, weight loss, malnutrition, or bowel obstruction) Transmission Fecal-oral, Ingestion of eggs directly from soil or on contaminated hands or produce Diagnosis Microscopic examination of feces (eggs) Treatment Albendazole, Mebendazole Prevention Sewage management, Hand washing, Proper food handling TRICHURIASIS (WHIPWORM INFECTION) Pathogen Trichuris trichiura Signs and Asymptomatic, Mild symptoms, Moderate to severe cases Symptoms (abdominal pain, diarrhea, weight loss, anemia, rectal prolapse) Transmission Ingestion of embryonated eggs from contaminated food, water or soil, Poor sanitation and hygiene practices contribute to infection spread Diagnosis Microscopic examination of stool (eggs) Treatment Mebendazole, Albendazole Prevention Proper disposal of human waste, Access to clean water, Hand washing, Periodic deworming programs, Education  NECATORIASIS (HOOKWORM INFECTION) Pathogen Necator americanus Signs and Few symptoms unless a heavy worm load induces nutrient Symptoms deficiencies Transmission Larvae penetrate the skin, often through bare feet Diagnosis Microscopic identification of eggs (stool) Treatment Albendazole, Mebendazole Prevention Sewage management, Wearing shoes  ENTEROBIASIS (PINWORM INFECTION) Pathogen Enterobius vermicularis Signs and Itchy anus, Disturbed sleep, Teeth grinding Symptoms Transmission Ingesting eggs that readily stick to hands or surfaces Diagnosis Tape adhesion test (egg detection) Treatment Pyrantel pamoate; When one person is diagnosed, need to treat the whole household simultaneously Prevention Hand washing  FIGURE 5.19 ▪ A micrograph of the nematode Enterobius vermicularis, also known as the pinworm. (credit: modification of work by Centers for Disease Control and Prevention)  FILARIASIS Pathogen Wuchereria bancrofti, Brugia malayi, Brugia timori Signs and Asymptomatic; Acute stage (fever, lymphangitis, swelling of Symptoms affected limbs), Chronic stage (lymphedema of the limbs, hydrocele, elephantiasis) Transmission Bite of infected mosquitoes (Culex, Anopheles, Aedes) Diagnosis Microscopic examination of blood (larvae), Antigen detection tests, PCR Treatment Diethylcarbamazine (DEC), Invermectin, Albendazole Prevention Periodic distribution of antifilarial drugs, Mosquito control measures, Insect repellents, Long clothing, Bed nets, Education  ONCHOCERCIASIS (RIVER BLINDNESS) Pathogen Onchocerca volvulus Signs and Severe itching, Skin rashes, Nodules under the skin, Vision Symptoms impairment (blindness in severe cases) Transmission Bites of infected black flies (Simulium spp.) Diagnosis Microscopic examination of skin snips (larvae), Serology testing (antibodies) Treatment Ivermectin Prevention Distribution of Ivermectin to communities in endemic areas, Control black fly populations, Education  SCHISTOSOMIASIS (BILHARZIA) Pathogen Schistosoma masoni, Schistosoma japonicum, Schistosoma haematobium Signs and Itchy rash when first infected; Within two months symptoms of Symptoms fever, chills, cough and muscle aches may develop Transmission Bare skin contact with contaminated freshwater via wading, bathing, swimming or washing Diagnosis Microscopy (eggs in feces or urine), Molecular methods (DNA), Antibody testing Treatment Praziquantel Prevention Avoid wading, swimming or washing in freshwater where disease is endemic, Proper sanitation measures, Vector management and control, Education TAENIASIS (TAPEWORM INFECTION) Pathogen Taenia solium (pork tapeworm), Taenia saginata (beef tapeworm) Signs and Asymptomatic; Mild abdominal discomfort, Nausea, Diarrhea, Weight Symptoms loss, Weakness, Segments of tapeworm may be visible in stool Transmission Taenia solium – consuming undercooked pork or ingesting food or water contaminated with feces containing eggs Taenia saginata – consuming undercooked beef Diagnosis Identification of proglottids or eggs in stool, Serology testing Treatment Praziquantel, Niclosamide Prevention Thoroughly cooking pork and beef, Hand washing, Avoid consuming raw or undercooked meat, Proper sewage disposal, Education ▪ Life cycle of a tapeworm.  CYSTIC ECHINOCOCCOSIS Pathogen Echinococcus granulosus Signs and Asymptomatic in early stages, Liver and lung cysts → Abdominal Symptoms pain, Nausea, Vomiting, Cough, Allergic reactions Transmission Ingestion of eggs from contaminated food, water or surfaces with fecal material from infected dogs Diagnosis Ultrasound, CT, MRI (to see cysts), Antibody testing Treatment Surgical removal of cysts, Albendazole Prevention Control dog populations, Proper disposal of dog feces, Avoidance of contact with dogs and contaminated environments, Education  ALVEOLAR ECHINOCOCCOSIS Pathogen Echinococcus multilocularis Signs and Slow growing tumor-like lesions (liver), Abdominal pain, Weight Symptoms loss, Jaundice, Fatigue Transmission Ingestion of eggs from fecally-contaminated food, water or surfaces (feces of infected foxes or other canids) Diagnosis Ultrasound, CT, MRI (to visualize lesions), Antibody testing Treatment Surgical removal of affected tissue, Albendazole Prevention Control fox populations in endemic areas, Avoid contact with potentially contaminated environments, Education on proper hygiene practices