Lec 24 - trypanosomiasis, WNV, schistosomiasis

Question 1

what are some common names for trypanosomiasis

Answer 1

sleeping sickness and chagas disease

Question 2

what are the scientific names of trypanosomiasis

Answer 2

African variants: trypanosoma brucei gambiense (TbG), trypanosoma brucei rhodensience (TbR)

american variant: Trypanosoma cruzi

Question 3

what are the species involved with trypanosomiasis

Answer 3

humans are the primary reservoir for TbG but ungulates and primates can host. cattle are the primary reservoir for TbR. all mammals are susceptible to T. cruzi

Question 4

what are the geographic location of trypanosomiasis

Answer 4

TbG is found in west and central africa

TbR is found in east and southeast africa

T.cruzi is found in the americas

Question 5

what are the clinical signs of trypanosomiasis in animals

Answer 5

• incubation period 1-4 wks
• primary signs - intermittent fever, anemia, weight loss, lethargy, vomiting, diarrhea
• chronic cases - swollen lymph nodes, serous atrophy of fat and anemia
• postmortem lesions: vary and nonspecific, can have extensive petechiation of serosal membranes in fatal cases

Question 6

what are the clinical signs of trypanosomiasis in humans

Answer 6

chills, headaches, muscle/joint pain, anemia, swollen lymph nodes

Question 7

what is the morbidity/ mortality of trypanosomiasis

Answer 7

influenced by general health of animal and can relapse with stress
- can have rapid death
- death with chronic untreated cases

Question 8

how is trypanosomiasis transmitted

Answer 8

african variants: vector borne disease carried by bites from the tsetse fly - spreads the protozoan trypanosoma

american variant: vector borne disease carried by bites form the kissing by (reduviid bug) carrying T.cruzi
- mammals that ingest the insects of the feces of the insects

Question 9

how is trypanosomiasis controlled

Answer 9

african variants: the best method of control is fly population control through environmental clean-up as well as using fly spray or dipping animals in insecticides specified as safe for dipping usage.

american variants: vector control of the environment through pesticides.

Question 10

how is trypanosomiasis treated

Answer 10

african variant: there are a variety of curative meds for sick animals. some over lap with prophylactics

american variants: there is currently no FDA approved treatment of chagas disease. the only method of treatment at this time is supportive care

Question 11

what is the one health impact of trypanosomiasis

Answer 11

is a major obstacle to rural economic development in some countries

Question 12

is trypanosomiasis a reportable disease

Answer 12

yes

Question 13

is trypanosomiasis zoonotic

Answer 13

yes

Question 14

what is the scientific name of west nile virus/ west nile encephalitis (WNV/WNE)

Answer 14

flavivirus family: orthoflavivirus nilense

Question 15

t/f the leading cause of mosquito-borne disease in the continental US

Answer 15

true

Question 16

what are the species involved with west nile virus

Answer 16

birds and alligators are the DH , they can infect humans, horses and other mammals (dogs, cats, chipmunks, squirrels)

Question 17

what are the clinical signs of WNV in humans

Answer 17

fever, headache, body aches, vomiting, diarrhea, and rash
severe: neuroinvasive disease: encephalitis, meningitis

Question 18

what are the clinical signs of WNV in horses

Answer 18

generally rare and mild but can cause neurologic disease
- lethargy, inappetence, ataxia, weakness, head and neck tremors, muscle fasciculations, opisthotonos, convulsions/paddling and recumbency

Question 19

what is the morbidity/mortality of WNV in humans, birds, and horses

Answer 19

humans: morbidity 20%, mortality 5%

birds: generally nonpathogenic but higher mortality rate in American birds

horses: morbidity 20% after development of neurological disease mortality rate 30%

Question 20

how is WNV transmitted

Answer 20

bite of an infected mosquito (primary culex species)
– mosquito feeds on infected birds or alligators
– humans and horses are dead end hosts

can spread through blood transfusions, organ transplantation (rare)

vertical transmission (mother to baby)
– pregnancy, delivery or breastfeeding

Question 21

what is the treatment for WNV

Answer 21

supportive care: rest, fluids and pain medications

horses with severe disease are often euthanized for humane reasons, rather than spontaneous death

Question 22

Is WNV a reportable disease

Answer 22

yes - it is a nationally notifiable disease, report to state vet of CDC

Question 23

what is the prevention for WNV

Answer 23

• there is no vaccine for humans (those who recover have life long immunity)
• vaccination for horses, depending on the area may booster up to 2-3 times per year

prevent mosquito bites
– use insect repellent, wear long sleeves and pants, treat clothing and gear
- mosquito trapping and arbovirus testing programs

Question 24

is WNV zoonotic

Answer 24

yes - people are a dead end host

Question 25

what is the common name for schistosomiasis (bilharzia)

Answer 25

snail fever

Question 26

what is the scientific name for schistosomiasis

Answer 26

schistosoma haematobium, S.japonicum, and S.mansoni

Question 27

what is the geographic location of schistosomiasis

Answer 27

s. mansoni is found primarily across sub-saharan africa, some south american countries and the caribbean s. haematobium is found in africa and pockets of the middle east S.japonicum is founf in china, the philippines and sulawesi

Question 28

what are the clinical signs of schistosomiasis

Answer 28

systemic symptoms: fever, cough, and eosinophilia abdominal pain, diarrhea, and blood in stool due to intestinal schistosomiasis hematuria, fibrosis of the bladder and ureter, kidney damage, genital lesions and infertility. occasionally central nervous system lesions are seen, causing granulomatous lesions around ectopic eggs in the spinal cord

Question 29

what are some postmortem lesions from schistosomiasis

Answer 29

hematuria, scarring, calcification, squamous cell carcinoma, and occasional embolic egg granulomas in the brain or spinal cord

Question 30

what are the morbidity/ mortality rates of schistosomiasis

Answer 30

morbidity rates are est to be 75 million cases globally per year mortality rates are est to be 11,792 deaths globally per year - both are likely sig underestimated

Question 31

how is schistosomiasis transmitted

Answer 31

eggs are excreted from humans through their urine into freshwater. the eggs contain miracidium (mature ciliated form). once in freshwater these eggs hatch, releasing miracidium. The miracidium penetrates soft tissue on their intermediate host bulinus snail - within these snails parasites undergo asexual reproduction via their sporocyst stages. it takes about 4-6 weeks fir them to mature enough to be shed into water - no cercariae, they penetrate mammalian hosts via skin contact, before spending 10-12 more weeks maturing into adult schistosomes - at this point these adults will start to produce eggs themselves within their host

Question 32

what is the treatment for schistosomiasis

Answer 32

praziquantel is the recomended dewormer of choice for this disease

Question 33

how is schistosomiasis controlled

Answer 33

education about the spread to this disease as well as trying to minimize the amount of contact people have with urine contaminated freshwater sources

Question 34

where does the parasite schistomas live in humans

Answer 34

this parasite lives primarily in the urogenital venules. - they feed off erythrocytes, and affect the vascularity of many corresponding urogenital organs (bladder, lower uterus, urethra, seminal vesicles, uterus) Other schistomes live within other organs including mesenteric venules where they release eggs into the host intestines

Question 35

what are some complications in females that can come from schistomiasis

Answer 35

they cause infertility and spontaneous abortion. they are also known to cause increased incidence of STIs (including HIV), UT obstruction which could cause CKD and in some severe cases cancer

Question 36

is schistosomiasis zoonotic

Answer 36

Yes