15: Zoonosis Examples Flashcards
chagas disease/trypanosoma cruzi host
many mammalian species recognised as reservoir host
- infects many animals and humans
parasite found in the faces of the triatomine bug (kissing bug)
bugs infect/bite animals/rodents
- infect animals, suck the blood of infected animals, etc.
bugs also live in small crevices
chagas disease infection
pathogen sucks blood which doesn’t cause transmission
they excrete faces
- scratch after they bite which rubs faces into the wound
allows pathogen to enter the bloodstream and infect the host
chagas disease
in mammals and humans, parasites hide in heart and digestive muscles
left untreated, it later causes serious heart and digestive problems eventually resulting in debilitating heart and/or intestinal disease
treatable if medicines are given soon after infection
statistics of chagas disease
10,000 deaths annually
25 million at risk (from lack of knowledge and lack of access to treatment)
prevention of chagas disease
no vaccine
insecticide spraying to get rid of the bug
- not treating the disease but killing the host to stop transmission cycle
home improvements
- filling up crevices in houses
good hygiene practices
personal preventive measures
screening of blood donors
testing of organ, tissue and cell donors and receivers
carlos chagas
described in detail a previously unknown infectious disease, its pathogen, its vectors, hosts, clinical manifestations and epidemiology
discovery recognised as one of the most important achievements in parasitology
nipah virus host
endemic to fruit bats living in SE Asia
virus doesn’t affect them but they carry it and spread it through bodily fluids like saliva/urine
nipah virus Malaysia 1997
transmission facilitated by intermediate hosts
- pig-pig and pig-human transmission by aerosol
parts of the forest burned to make space
- bat populations had to go elsewhere
moved closer to mango trees with human populations
- dropping saliva, feces on the floor
- pigs eating leftover mangoes on the floor
virus transmitted to pigs, who got sick and transmitted to farmers as well
now, separate fruit trees and pigs
nipah virus yearly outbreaks in bangladesh since 2009
associated with palm trees where people get juice
- scar them for sap collected with a container
fruit bats come at night and excrete feces into those containers
transmission of virus into containers so people get infected
cover scars of trees with nets/fences to prevent bats which did prevent most outbreaks
3 outbreaks of nipah virus in india
west bengal 2001
west bengal 2007
kerala 2018
- bats found in water wells where people were getting water
- covering up wells with nets to prevent bats from nesting again
regular nipah outbreaks
major issue/concern
- virus spilling over into the human population on a regular basis
worrisome range of bats carrying the nipah virus
doesn’t spread human-human but it could mutate and cause a bigger different virus
nipah disease
encephalitis
incubation period of 5-14 days
illnesses presents with 3-14 days of fever, headache, drowsiness, disorientation and mental confusion
can progress to a coma
case fatality rate between 45% but can go over 80%, depending on the outbreak
west nile virus transmission cycle
reservoir in many kinds of birds but transmitted through mosquitos
- mosquito bites infected birds, gets infected, virus replicates in mosquitos
- mosquitos go on to bite other birds, transmitting the disease
once in a while, infects humans and horses
no human-human transmission
- humans/horses get sick from the virus but no virus in the blood to be picked up even after infection
- one way street since they’re dead-end hosts who get sick but do not transmit the disease
west nile virus as the leading cause of mosquito-born disease in the continental US
about 1 in 5 infected develop a fever and other symptoms like headache and fatigue
about 1 in 150 infected people develop a serious, sometimes fatal illness like encephalitis and meningitis
no specific treatment for west nile virus infection
no licensed west nile virus vaccine for people (but there are for horses)
