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Flashcards in WK 4- One Health Deck (15):

What is one health

describes the field of research and practice integrating human, animal and ecosystem health to address health hazards at the human-animal-ecosystem interface


What is the epidemiology of leptospirosis

widespread disease that occurs most frequently in both temperate and tropical regions- most at risk are those who work with animals or in the outdoors, especially around water


What is the lifecycle of leptospirosis

1. The bacteria can enter a host (either a reservoir host or a non-carrier host) via portals such as damaged skin or mucous membranes
2. Once inside the host, the pathogenic strains will either be eliminated by the immune system, or will reproduce and spread to the blood stream and lymphatic system
3. Reservoir hosts, most commonly rats, will harbour the bacteria and shed it via urine
4. Bacterial strains passed in the urine are able to survive in soil and water for extended periods of time and infect hosts via entrance through the skin or mucous membranes


How is leptospirosis transmitted

The leptospira bacteria is transmitted through the urine of infected animals, including; cattle, pigs, horses, dogs, rodents and wild animals. Humans can become infected if they are in direct contact with animal urine or through contact with food, water or soil contaminated with infected animal urine. The bacteria mainly enters the body through the skin (especially if broken) or mucous membranes.


What is the clinical presentation of leptospirosis

wide range of generalised symptoms including; fever, headache, chills, myalgia, vomiting, diarrhoea, abdominal pain and a rash. In severe cases, the patient may also experience kidney or liver failure (Weil disease) or meningitis.


What is the incubation period of leptospirosis

The incubation period can range from 2 days – 4 weeks and symptoms generally subside after 3 weeks if treatment is sought.


What is the life cycle of schistosomiasis

eggs are eliminated in faeces/urine into the water→ when the eggs hatch they release miracidia which enter the intermediate host (a freshwater snail)→ in the snail the miracidia become sporocysts and then cercariae→ Upon release from the snail, the infective cercariae swim, penetrate the skin of the human host and shed their forked tail, becoming schistosomulae→ Adult worms in humans reside in the mesenteric venules in various locations


How do schistosomulae (schistosomes) cause disease

Can become stuck in organs and cause fibrosis


What is the clinical presentation of schistosomiasis

Fever, rash, chills, muscle aches, abdominal pain (portal hypertension)
→ chronic schistosomiasis= abdominal pain, fibrosis, enlarged liver, blood in the stool or blood in the urine, and problems passing urine. Chronic infection can also lead to increased risk of bladder cancer (dysuria, haematuria)


How is schistosomiasis treated

Praziquantel, a prescription medication, is taken for 1-2 days to treat infections caused by all Schistosoma species


How is schistosomiasis prevented

PPE, control of freshwater snail through treatment of the water, public sanitation, water drainage channels, using prawns to eliminate the schistosomes


What is the lifecycle of cysticercosis

1. eggs are passed in human faeces into water/environment→ 2. the egg can then either infect humans, or pigs→ 3. in the pigs, the eggs can hatch and release oncospheres that penetrate the intestinal wall and move to the muscle to create cysts with cysticerci → 4. if a human consumes pork that has not properly been prepared, the cysticerci can be ingested and then hatch into adult tapeworms (aka taenia solium)--> 5. if the human ingests the eggs (can also be through unprepared vegetables or contaminated water) then the cysticerci will move into subcut tissues/eyes/brain and cause cystercercosis


How does cysticercosis present

-affects CNS, skin, muscle, eyes
-mainly asymptomatic if not in eye/CNS
-neurocystercicosis= lethargy, epilepsy (main cause), cranial haemorrhage→ cysts can be in brain, eye or spinal cord


How do you treat cysticercosis

cysticidal drugs (praziquantel), may require shunt installation, anti-epileptics


How do you prevent cysticercosis

combination of human anthelmintic treatment with albendazole and hand washing, prepare and store food safely, vaccination of pigs, mass drug administration for taeniasis, health educationcombination of human anthelmintic treatment with albendazole and hand washing, prepare and store food safely, vaccination of pigs, mass drug administration for taeniasis, health education