Taenia solium Zambia Flashcards
Taenia solium: what are intermediate hosts (normal/rare) and accidental host?
Intermediate host: Pig
Rare intermediate host: Dog
Accidental host: Human (dead end) if we get cysticercosis, intermediate host if we get taeniosis
Taenia saginata: what is the intermediate host?
Cattle/cows
Can neurocysticercosis be transmitted from human to human?
No, unless you don’t eat human flesh xD
Lifecycle of taenia solium: (Starting from taeniosis)
1) Infected human host starts to excrete eggs from anus, eggs can leave as proglottids, which is a huge source of eggs, or eggs can leave separately (taeniosis)
The eggs are immediately infectious
2) Once pigs eat those eggs from contaminated environment, pig gets infected (porcine cysticercosis) Eggs develop in the meat, muscle and brain, to small larvae.
3) Once the contaminated meat of pig is consumed, we get the infection back, which might also lead to human cystercercosis or neurocystercercosis
*After a while, eggs get calcified and degenerated, infectiousness only happens in viable cyst stage
Pig gives humans meat: Tapeworm develops in humans
Human feces contaminates environment, and human eats contaminated food etc. : cystercycosis
Neurocystercycosis: also human to human, source is feces
What’s the problem in Africa? (that causes the spread of Taenia?)
1) No meat inspection/backyard slaughtering: people consume extremely heavily infected meat and they even like it
They carry it to market in baskets in high temperatures in Zambia, ideal for pathogens
This is also poverty-related: although they might know its infected, they still sell it on markets, they don’t want to bring it to meat inspection and take risk either
-Even if they do meat inspection: it has low sensitivity (only picks up heavily infected ones, few cysts are missed)
-People don’t give more money for clean food either usually
2) They don’t cook meat properly, only grilled shortly in cafes and bars
2) People are often farmers or have farm animals: so close to animals, but they don’t take care of animals much
Pigs have access to stool, they free roam, no need to take care of them, so pig numbers keep increasing
They can even enter to toilets, if toilets aren’t built properly
They just often build them little stables to keep them at night from predators, thieves, people etc. but pigs go out from them easily
Humans need to put manpower and resources (although there’s swine flu), normally pigs just find their own water and food
In West: if you need to kill your animals, often farmers are reimbursed, so there’s compensation - but here you cant convince farmers to invest
Feeding pigs often is not possible
3) People often don’t realize they are infected, because proglottids do not crawl out of their anus as Saginata does.
4) Personal sanitation is very low, even hand washing: people might just come out of the toilet and carry the eggs on their hands
They don’t have proper toilets, often no privacy, no doors or see-through toilets, also they look really disgusting because no flush
Kids are often scared of toilets because its a really deep pit: afraid of falling inside at night
Often toilet construction starts by governments, NGOs, not finished sometimes, they use those toilet stones as door stones xD
People even use human feces as fertilizer xD
It’s not just about poverty though: their behavior is problematic
Why studying Taenia is important?
Most important foodborne parasite: because has the highest DALY in foodborne parasites especially due to the possibility of neurocystercycosis
What happens in cysticercosis/neurocysticercosis in humans?
1) Muscle or subcutaneous infections observed
2) Or in other organs such as eyes
3) Neuro version: CNS/Brain gets infected: Swiss cheese brain lmao.
Taenia solium symptoms in humans? (taeniasis, cysticercosis, neurocyst stages)
1) Taeniosis: Like regular tapeworm infection, mostly asymptomatic or mild GI complaints: abdominal pain, diarrhea, vomiting, weight loss
People don’t realize the infection because proglottids do not crawl out of their anus. Taenia saginata it does.
2) Cysticercosis: %50-70 asymptomatic, or mild muscl complaints
3) Neurocystercercosis: Also mostly asymptomatic, depends on where cysts are in brain, also whether the cysts are viable or not
Cysts often calcify to hide from immune system and go dormant = that’s when they are recognised by immune system and the symptoms occur = so host reaction causes the symptoms in neurocysticercosis often.
But its the main cause of acquired epilepsy (%57 of them)
Taenia solium symptoms in pigs
We thought it was completely asymptomatic, but pigs in Africa are not monitored anyway/they free roam. A study monitored the pigs 24/7 and saw that actually, heavily infected animals get seizures and behavioral changes. Pig welfare and health definitely decrease.
Where are the Areas that taenia solium is most observed?
Subsaharan africa, latin america, asia
Infection study results in Zambia?
(EITB?) in this setting: checks the exposure/not active infection
Other Ag- ELISA: checks the active infection
Crazy levels of infections, normally in endemic areas rate of infection are around 0.1%, 1% = here it is %35 in some areas. Pig infections are also very high, almost %50 in some areas.
They checked whats the effect of this infection on neurocystercycosis: it’s the most important cause of epilepsy in this area, %57 of them have neurocyst.
Epilepsy treatment is really an issue in Africa: because they think people are rather possessed by witchcraft rather than treating these people.
How can we break the transmission cycle of Taenia solium?
1) Prevent people from eating/drinking contaminated things:
-Cook the meat properly
-Wash vegetables with clean water (often surface water is contaminated, maybe boil it)
-Build proper health education
Make them throw heavily infected carcass away, hard to do due to poverty.
What they actually do: if less infected, watch them boil it.
International regulations rather say to destroy any contaminated food though.
2) Prevent worm localization in the intestine
- Treatment: Note: whole worm often crawls out of the body after treatment: make sure it’s not openly defecated
3) Prevent eggs from going into the environment
- Build proper toilets, also use them
- Don’t use human feces as fertilizer
- Build proper sewage, water purification systems
4) Prevent pig infection
- Keep the pigs away from toilets / enclose them completely if possible
- No free-ranging/feeding w stool
-Or vaccinate them
5) Prevent infection growing inside pigs
- Treat them
6) Prevent infected carcasses from entering food chain
-Do meat inspection/don’t let them even be brought to markets
During meat inspection: heavy infection: directly burn the meat
light infection: do incisions, if 1-2 cysts are observed: force it to be boiled. Even the infections observed were calcified, there might be active infections elsewhere.
Normally freezing would be an option, but no electricity in Africa
Community led Total sanitation (CLTS)?
- Methodology implemented to completely eliminate open defecation, also supported by unicef & governments
- Communities do it on their own: not imposed on them from outside countries etc.
- At the end, they realize their own behavior and decide to make their villages open defecation free
- Done to change their behavior
1) People meet in community meetings and use the word “shit” not feces or stool
2) Do a open defecation mapping: Mark the location of shit on map, visualize it, and discuss it openly: say these ones are still fresh and ask who did it lol
3) And shame the people who did it, walk of shame/disgust
4) Calculate the shit produced every day by village: in a number of bags they can quantify, so that they will understand how big the problem is
5) Do food shit exercise: Put a bottle of water/food near open defecation and wait, see flies flying around it: grab it and ask people whether they want to drink it now
6) Also calculate how much does this cost to them: medical expenses and everything bcs people get sick due to open defecation
7) Eventually, people get disgusted and shocked- so they make a plan: they start to construct proper latrines coupled with hand washing+soup/sand
8) Once they accomplish their plan: they put a sign saying “they are a open defecation free village”
How good CLTS work - study in Zambia
They observed some activity for sure in villages after CLTS, people started constructing pits everywhere (was actually dangerous xd)
- Ag-ELISA showed no decrease in T. solium infection in pigs, so no change in Taenia
- Also no decrease in human cystercycosis is observed, it even slightly increased xD-This is because: in Taenia, even 1 infected person openly defecated: everyone gets infected, really hard to tackle - full coverage needed
BUT: it showed increased toilet ownership/also quality of toilets improved significantly
-No village reached complete open defecation free status/universal latrine coverage
Some villages contributed significantly, some villages didn’t care: also depends on their leaders
Questionaire: Obstacles/good things in implementing toilets?
Pros:
- They are happy that hygiene improved, flies reduced, pigs stopped eating feces, -pigs cannot push you away before you finish? apparently, they follow you to the toilet and wait for you to shit so that they can eat it.. bruh
- It’s also coupled with hand washing
- Bushes that they use for shitting was often too far away, so they liked closer toilets better xD
- Once built properly: it improved their dignity, privacy, and they found it more comfortable
- Less possible to meet with shitting family members around
- It reduced diarrhea and diseases, and toilet is better
- People realized they were eating feces lol xD
- Also they stopped pigs to bring diseases to them
- They said there’s nothing good about open defecation lol
Cons:
- Toilets were not built properly or did not last long: if you don’t build them properly people cannot go at morning, they wait for night
- Money and materials for the toilet is hard to find
- Building a latrine in this area is apparently a job of men: For unmarried women, no one built toilets for them, they needed logs etc.
- Planting or harvesting work slowed in progress/bcs everyone was building toilets
- It’s simply not a habit to use toilets, BRUH, they like shitting open xD
- Government did not really followed up or supported/no people to help them out
- Men were also lazy, or too drunk xD?
- Also they were saying: oh I don’t need toilet bcs my neighbor has one
- Open defecation is not banned by law
- Not enough education on whether their toilet is sufficient or not xD
- not very effective in preventing diseases if not everyone has a toilet/uses it
- People cannot really talk about toilets? they were saying they going to post a mail or something or adults act like they arent shitting to the children
- Their culture doesn’t allow them to use same toilets with family members, especially elderly
