Parasites3 Flashcards
Giardia spp.
- Giardiasis
- Motile (feeding) form lives in small intestine
- Cyst form is passed in feces
- Incubation period is 3 to 35 days
Importance, Diagnosis, Transmission Giardia
- Importance→diarrhea
- Diagnosis→ Fecal direct smear with iodine
- Transmitted by ingestion of contaminated feed or water.
Treatment of Giardia
Metronidazole (Flagyl®)
Fecal antigen test available
Syndrome of Giardiasis
Human– usually asymptomatic
• – nausea, vomiting, diarrhea, abdominal pain, bloating
Animal– subclinical
diarrhea, wt. loss
Occurrence of Giardiasis
Most common parasitic infection in developed countries- rate of infection is
1-30% in surveyed stool samples
Control and prevention of Giardiasis
Personal hygiene
Protect water supplies from contamination w/ feces
Filter public water supplies
Babesia canis
- Bloodborne parasite
* Microscopic parasite visible under high power magnification in a blood smear
Importance, Diagnosis, Control of Babesia canis
- Importance- can cause hemolytic anemia
- Diagnosis- stained blood smear, Ab test
- Control- treat infected animals, tick control
Cryptosporidiosis
• Disease caused by a protozoan parasite capable of infecting many animals
• Causative organism: Cryptosporidium parvum
Smaller than giardia cyts
• Incubation period is 3 to 7 days
Occurrence, Transmission of cryptosporidiosis
- Occurrence- Infection found in 1-4.5% of stool samples surveyed in the U.S. and Europe
- Transmission- Ingestion of oocysts passed in animal or human feces
Diagnosis, Treatment of cryptosporidiosis
- Diagnosis- Microscopic examination of feces for oocysts, fecal antigen test
- Treatment- Nitazoxanide, supportive care
Control and prevention of cryptosporidiosis
o Good personal hygiene
o Dispose of feces in a sanitary manner
o Filter public water supplies
o Immunocompromised individuals should avoid contact w/ diarrheic animals or people
Toxoplasmosis
- Protozoal disease transmitted from cats to humans
- Causative organism: Toxoplasma gondii
- Incubation period is 1 to 4 weeks (average 7-14 days)
Syndrome of Toxoplasmosis
• Human-- usually asymptomatic fever, swollen lymph nodes cardiac, pulmonary, and CNS dz. birth defects • Animals-- usually subclinical -- abortion in sheep, pigs, and goats
Mortality, Transmission of Toxoplasmosis
• Mortality- Low, higher risk for immunocompromised individuals, newborns, fetus
• Transmission
o Ingestion of oocysts in cat feces
o Ingestion of cysts from infected meat
Diagnosis, Treatment of Toxoplasmosis
- Diagnosis- Serology
* Treatment- Antiparasitics
Control and prevention of Toxoplasmosis
o Avoid contact w/ cat feces or contaminated soil
o Cook meat thoroughly
External Parasites
- “Ectoparasites”
- Live or feed upon the skin of an animal
- Their presence is referred to as an “infestation”
- Two groups of arthropods are the most important external parasites= Insects and Arachnids
Arachnids
- Ticks, mites
- Body divided into 2 segments: a fused head/thorax and an abdomen
- 8 legs originate from the abdomen of the adult parasite
Insects
• Lice, fleas, flies
- Body divided into 3 segments: head, thorax, abdomen
- 6 legs originate from the thorax
Damage caused by external parasites
o Irritation- biting and crawling
o Loss of body conditionà decrease food intake
o Anemia- blood loss
o Disease transmission- Ehrlichiosis, lyme disease, rocky mountain spotted fever
Diagnosis of infestation of external parasites
o Some visible to the naked eye
o Some easily collected by skin scraping for microscopic identification
Transmission, Diagnosis, Treatment of Giardiasis
- Transmission- Ingestion of cysts passed in the feces of infected humans or animals
- Diagnosis- Microscopic examination of feces for cysts, fecal antigen test
- Treatment- Antiparasitics
Sarcocystosis
- Disease caused by a protozoan parasite found in beef or pork
- Causative organism: Sarcocystis spp.
- Incubation period is 2 weeks
Syndrome of Sarcocystosis
o Human– usually asymptomatic
o nausea, diarrhea, discomfort
o Animal– subclinical
Transmission of Sarcocystosis
o Ingestion of infected raw or undercooked beef or pork
o Ingestion of oocysts in human feces
Occurrence, Diagnosis, Treatment of Sarcocystosis
- Occurrence- Common in underdeveloped countries w/ poor hygiene
- Diagnosis- Microscopic examination of feces for oocysts
- Treatment- Antiparasitics
Control and prevention of Sarcocystosis
o Good personal hygiene
o Prevent contamination of livestock feed w/ human feces
o Cook meat well
Syndrome of cryptosporidiosis
o Human– asymptomatic
– anorexia, nausea, vomiting, watery diarrhea, abdominal cramps
o Animal– watery diarrhea in calves 1-2 weeks old, can cause death
Seasonal variation of external parasites
o Ectoparasites that spend their entire life cycle on the host are a problem year round
o Ectoparasites that spend part of their life cycle off the host need warmth to proliferate more effectively
Ctenocephalides spp.
- “Flea”
- Adult is 3-4 mm flattened laterally w/ powerful legs for leaping, piercing/ sucking mouth parts
- Eggs 0.5 mm white, oval
Importance, Diagnosis, Control of Ctenocephalides
- Importance- Irritation and itching, loss of body condition, flea allergy dermatitis, disease transmission
- Diagnosis- Fleas and flea dirt in hair coat
- Control- Treat host and environment w/insecticide
Plague
• One of the oldest diseases affecting man
• Caused by a bacteria maintained in rodent populations
o Yersinia pestis
• Incubation period is 2 to 6 days
Syndrome of Plague
o Human– fever, chills, myalgia, sore throat, headache
lymph node enlargement (bubonic)
septicemia w/ development of pulmonary disease
o Animal– rodents become ill and die
cats may develop fever, dyspnea, nasal discharge, swollen lymph nodes, septicemia
Mode of transmission of Plague
o Bite of an infectd rodent flea
o Handling tissues or fluids of infected animals
o Inhalation of airborne bacteria from cats or humans w/ pulmonary disease
Diagnosis and Treatment of Plague
- Diagnosis- Culture of lymph node aspirate, blood, sputum, CSF
- Treatment- Antibiotics
Control and prevention of Plague
o Prevent human contact w/ wild rodents
o Use insecticides/ repellents when entering wildlife habitats
o Wear gloves when hunting or handling wildlife
o Keep dogs and cats from hunting wild rodents
o Vaccinate individuals at risk
Otodectescynotis
- “Ear Mite”
* Adult is 0.4 mm, dorsoventrally flattened w/ 8 legs
Importance, Diagnosis, Control of Otodectescynotis
- Importance- External otitis
- Diagnosis- Examine debris from external ear canal
- Control- Clean ears, apply miticide
Cheyletiella spp.
- “Fur Mite”
- Adult is 0.4 mm, has hook-like palpi
- Importance- Alopecic dermatitis
- Diagnosis- Skin scraping
