Parasitology Nutrition PDF

MICRO 205 Microbiology & Parasitology Medical Parasitology Dr. Elfadil Abass 1  Module Objectives Recognize the basic concept of human parasites and parasitic diseases Describe different types of parasites transmitted through food and their related disea...

MICRO 205 Microbiology & Parasitology Medical Parasitology Dr. Elfadil Abass 1  Module Objectives Recognize the basic concept of human parasites and parasitic diseases Describe different types of parasites transmitted through food and their related diseases. 2  What is parasitology? – The study of parasites and their relationships to their hosts What is parasite? – An organism (can be microorganism) that lives within or on another organism called the host (human, animals, …) – Parasitology has traditionally been limited to parasitic protozoa, helminths (worms) and arthropods (medical insects). 3 Impact of Intestinal Parasitic Infections Intestinal parasitic infections impact the nutrition Undernutrition predispose individuals to parasitic infection – Adult worms reside in the small intestine and interfere with host nutrition and can induce damage to the intestinal mucosa that may reduce a person’s ability to absorb nutrients – The most significant cause of nutritional stress resulting from helminth infection is hookworm associated iron- deficiency anemia. 4  Host-parasite relationship (1) Commensalism – In which the commensal (organism) feeds on substances ingested by the host – An association between two organisms in which one benefits and the other neither benefit nor harm Entamoeba coli is a non-pathogenic species of Entamoeba that frequently exists as a commensal parasite in the human gastrointestinal tract. 5  Host-parasite relationship (2) Mutualism – Is an association in which the mutualist (organism) and the host depend on each other physiologically Describes the ecological interaction between two or more species where each species has a benefit Give and take (both benefit) 6  Host-parasite relationship (2) Mutualism – An alligator and birds relationship is mutualism – The alligator gets its teeth cleaned by the bird – The bird gets its food from the alligators' teeth. 7  Host-parasite relationship (3) Parasitism – Is type of relationship between two organisms – One organism (the parasite) benefit, while the other (the host) suffers (i.e causes a disease) – The parasite is physiologically dependent- the relationship may be permanent or temporary: Obligatory parasites (ALWAYS) are physiologically dependent upon the hosts- can’t survive isolated from them (Trichomonas vaginalis, Nectar americanus) Facultative parasites (SOME TIME) are free-living parasites that can be parasitic (Naegleria fowleri). 8  Host-parasite relationship (3) Parasitism – Parasitism usually involves (unlike commensalism and mutualism), in addition to the physiologic dependency of the parasite, immunological responses by the host – The host typically responds to the presence of the parasite is the production of antibodies. 9  Host-parasite relationship (3) Parasitism – Major types of parasites are classified according to location into endoparasites and ectoparasites – Endoparasites: Live within the body of the host (alimentary tract, liver, lungs, urinary bladder, blood) – Malarial parasites (Plasmodium spp) – Sleeping sickness parasites (Trypanosoma spp), have infective stages in the host's blood which are transported to new hosts by biting insects. 10  Host-parasite relationship (3) Parasitism – Ectoparasites: Are attached to the outer surface of the host or are superficially embedded in the body surface – Such as bed bug, ticks, and lice – Ectoparasites are associated with poor hygiene. 11  Host-parasite relationship Host classification: – The host may be classified according to its role to: (1) Definitive host, a host wherein the parasite reaches its sexual maturity (sexual form of life cycle occur) – Mosquitoe is the definitive host for malaria – Human is the definitive host for taeniasis (2) Intermediate host, if it serves as a temporary, but essential, environment for the development of the parasite – Human is the intermediate host for malaria – Pigs and cattles are the intermediate hosts for taeniasis. 12  Host-parasite relationship Host classification: (3) Transfer host (mechanical vector), if it is not necessary for the completion of the parasite’s life cycle but is utilized as a temporary vehicle for reaching a host House flies (Musca domestica) are transport hosts for a variety of protozoan parasites in addition to viral and bacterial pathogens Cockroaches act as mechanical vectors for various enteric parasites. 13  Host-parasite relationship The vector? – Is an arthropod or invertebrate that serves as a host and as a carrier for a parasite The vector is essential for completion of the life cycle (unlike the transfer host) The term is used to describe arthropods that transmit a parasite to the human or vertebrate host: – Mosquitoes are the vectors for malaria parasites and transmit the organisms to humans – Sand flies are the vectors for leishmaniasis – Tsetse flies are the vectors for African trypanosomiasis. 14  Host-parasite relationship The reservoir host? – Infected animals that serve as sources of infective organisms for humans are known as reservoir hosts – Rodents are reservoir hosts for leishmaniasis. 15  Classification of medically important parasites The causative agents of parasitic diseases of humans include: Protozoa (uni-cellular) Flatworms (Trematodes and Cestodes) Roundworms (Nematodes) Arthropods (insects, ticks, and lice). 16 17  Classification of medically important parasites Protozoology: – Study of protozoa, unicellular eukaryotic microorganisms Helminthology: – Study of parasitic helminthes (worms) including multicellular parasites with organs (known as metazoa) Entomology: – Study of arthropods (insects). 18  Transmission of Parasitic Diseases Food- foodborne parasites Water- water-borne parasites Animals- zoonotic parasites Blood, blood-borne parasites Insects, vector-borne parasites Congenital. 19  Transmission of Parasitic Diseases Food: – Numerous parasites can be transmitted by food including many protozoa and helminths – Some most common foodborne parasites are: 1. Protozoa: Giardia intestinalis, Entamoeba histolytica, Toxoplasma gondii, Cryptosporidium spp., 2. Nematodes: Ascaris lumbricoides, Enterobius vermicularis, Trichuris trichiura 3. Cestodes: Taenia spp, Hymenolepis nana. 20  Transmission of Parasitic Diseases Food: – Many of food-borne parasites can also be transmitted by water, soil, or person-to-person contact – Foods include: 1. undercooked seafood- fish, crabs 2. undercooked meat 3. raw vegetables that have been contaminated by human or animal feces – Some foods are contaminated by food service workers who practice poor hygiene or who work in unsanitary facilities. 21  Transmission of Parasitic Diseases Food: – Symptoms of foodborne parasitic infections vary greatly depending on the type of parasites: Abdominal pain, diarrhoea Muscle pain, cough, skin lesions Malnutrition, weight loss Neurological symptoms Other symptoms depending on the particular organism and burden of infection. 22  Transmission of Parasitic Diseases Water: – Water can become contaminated by parasites and can cause a variety of illnesses – Common water-borne parasitic diseases include: Amebiasis Giardiasis Schistosomiasis Guinea worm disease Cryptosporidiosis (Crypto) – People become infected when they swallow – Have contact with water that has been contaminated by certain parasites. 23  Transmission of Parasitic Diseases Water: – Amebiasis: Drinking water contains with fecal materials containing Entamoeba histolytica – Guinea worm disease: Drinking water contains Dracunculus medinensis When infected person with an open Guinea worm wound enters water used for drinking, they can spread the parasite into the water and continue the cycle – Schistosomiasis: Swimming in water that are contaminated with Schistosoma spp. 24  Transmission of Parasitic Diseases Animals (zoonotic): – Animals can carry parasites and pass parasites to people – A zoonotic disease: Is a disease spread between animals and people (viruses, bacteria, parasites, fungi) Foods can be the source for some zoonotic infection when animals such as cows and pigs are infected with parasites (Taenia spp, Trichinella spiralis). 25  Transmission of Parasitic Diseases Blood: – Some parasites can be blood-borne! 1. The parasite can be found in the bloodstream of infected people 2. The parasite might be spread to other people through exposure to an infected person’s blood: – Blood transfusion – Sharing needles or syringes contaminated with blood. 26  Transmission of Parasitic Diseases Blood: – Blood blood-borne diseases include: African trypanosomiasis (tsetse fly) Chagas disease (American trypanosomiasis) (bug) Malaria (mosquito) Babesiosis (tick) Leishmaniasis (sand fly) Toxoplasmosis (contaminated food) – Many blood-borne parasites are spread by insects (vectors), so they are also referred to as vector- borne diseases. 27  Transmission of Parasitic Diseases Blood transfusions: – Factors affect whether parasites that can be found in the bloodstream might be spread by blood transfusion: 1. how many parasites might be found in the blood (the concentration or level of the parasite- parasitaemia) 2. how long the parasite stays in the body, in treated and untreated people (time) 3. how the parasite affects people (symptomatic vs asymptomatic). For example, if infected people feel sick, they might not want to donate blood or they might be deferred. 28  Transmission of Parasitic Diseases Blood transfusions: – Some parasites spend most or all of their life cycle in the bloodstream, such as Babesia and Plasmodium species – Parasites, such as Trypanosoma cruzi, might be found in the blood early in an infection (acute phase) and then at much lower levels later (chronic phase of infection) – Other parasites only migrate (travel) through the blood to get to another part of the body … this infection has very low risk to be transmitted compared with the number of blood transfusions. 29  Transmission of Parasitic Diseases Blood transfusions: Blood Donor Screening – Potential blood donors are asked about: History of infection Recent international travel – People who travelled to malaria endemic areas are deferred from donating blood (former residents of malaria-areas should will be deferred for 3 years. People diagnosed with malaria shouldn’t donate blood for 3 years after treatment) In Saudi Arabia, donated blood is tested for a number of infectious agents, including malaria. 30  Transmission of Parasitic Diseases Insects: – An insect that transmits a disease is known as a vector – The disease is referred to as a vector-borne disease – Insects can act as: Transfer host (mechanical vectors): – The insect can carry an organism but the insect is not essential to the life cycle, such as house flies carry organisms on their bodies Obligatory hosts: – Where the disease-causing organism must undergo development before being transmitted, such as mosquito. 31  Transmission of Parasitic Diseases Disease Parasite Insect (vector) African Trypanosoma brucei Tsetse flies trypanosomiasis gambiense (sleeping sickness) Trypanosoma brucei rhodesiense Chagas disease Trypanosoma cruzi Triatomine (“kissing”) bugs Babesiosis Babesia microti and Babesia microti: ticks other species Leishmaniasis Leishmania species Phlebotomine sand flies Malaria Plasmodium species Anopheles mosquitoes 32  Transmission of Parasitic Diseases Congenital: What is congenital transmission? – Congenital infections are infections transmitted from mother to child during pregnancy (transplacentally) or vaginal delivery – They have the potential to adversely affect fetal development and long-term neurodevelopmental outcome What parasites can be transmitted congenitally? – Toxoplasma gondii – Trypanosoma cruzi – Plasmodium spp. 33  Assignment: Foodborne parasites and nutrition Aim: – Explore the interconnections between foodborne parasites and nutrition – Understand the role of parasites in food safety and how they contribute to malnutrition, especially in vulnerable populations. 34  Assignment: Foodborne parasites and nutrition Objectives: – Identify common foodborne parasites and explain their transmission routes – Analyze the nutritional challenges caused by parasitic infections – Explore prevention strategies, including public health interventions and food safety practices – Evaluate the role of nutrition in building immunity against parasitic infections. 35  Assignment: Foodborne parasites and nutrition Topics: 1. How do foodborne parasites contribute to malnutrition in affected populations? 2. Why are populations with poor sanitation and food insecurity more vulnerable to food-borne parasitic infections? 3. How do foodborne parasitic infections affect specific nutrients, and what are the long-term consequences? 4. What strategies can be implemented to reduce the incidence of foodborne parasitic infections, especially in malnourished communities? 5. What role do climate change and globalization play in spread of foodborne parasites & their nutritional impact?. 36  Assignment: Foodborne parasites and nutrition Structure: – Introduction: Introduce foodborne parasites and their relevance to nutrition – Main Body: Provide evidence-based discussions on the chosen topic, supported by research – Conclusion: Summarize your findings and offer recommendations for further research or public health interventions – References: Cite at least 5 credible sources (peer-reviewed journals, books, or reputable websites) Length: not less than 2,000 words, excluding front page Formatting: Use APA citation style, 12-point Times New Roman, and double-spacing. Deadline: ?? 37