The Piroplasms – p. 166-169 Piroplasms are members of the Phylum Apicomplexa that use ______________________________. Two are of _____________________________but one species does infect humans.
Babesia bigemina Causative agent of ___________________________________________ – of veterinary importance In infected cattle, parasite causes massive destruction of erythrocytes, resulting in _________________________________________ - death occurs in 1 week
Babesia bigemina VECTOR - _________________________________ HISTORICAL NOTE - This was first protozoan shown to be vectored by an arthropod. Smith and Kilbourne in 1893 worked out the life cycle. This finding lead others trying to work out life cycles of malaria, kala azar, sleeping sickness, etc. to consider arthropods as vectors.
Life Cycle of Babesia bigemina • 1. An infected tick bites cattle releasing __________________________ into the cow bloodstream. • 2. Sporozoite penetrates a rbc and becomes a _______________________. • 3. Trophozoite undergoes binary fission - 2 trophozoites often appear attached anteriorly (diagnostic!). • 4. Rbc is destroyed and trophozoites reinvade new rbc's • this asexual cycle continues indefinitely until the host dies.
5. Feeding tick picks up rbc's with trophozoites. • 6. Trophozoites penetrate cells of many organs and undergo schizogony to release __________________________. • 7. Some merozoites enter the tick's ovaries and eggs & are transmitted to the next generation of ticks by ________________________________. • 8. Merozoites undergo schizogony in tick offspring and infective stage _____________________________ are produced • sporozoites migrate to the tick salivary glands • transmitted to cattle with next tick bite.
Babesia bigemina PATHOLOGY - ____________________ __________________________________ - Older cattle are more severely affected. - Symptoms: loss of appetite, fever, listlessness, bloody urine - death common TREATMENT - Suramin & Berenil - drugs effective against Trypanosoma brucei are effective against Babesia - reason is unknown Trophozoites in cattle rbc’s
Babesia bigemina DISTRIBUTION - occurs throughout cattle-growing areas of Africa, South America, Europe, and Australia In U.S. ? Trophozoites in cattle rbc’s
Babesia canis Infects dogs throughout the world VECTOR - (Rhipicephalus sanguineus) PATHOLOGY -
Babesia microti This species normally occurs in ________________________________, but recent cases of it have been reported in humans. Causes _________________________________________- reported in Massachusetts (first report in 1975), New York, Rhode Island, and Wisconsin -2 cases in Wisconsin were identified in 1983 - See following report from Wisconsin Epidemiology Bulletin.
Babesia microti VECTOR - ______________________________ - larvae and nymphs feed on meadow voles to pick up infection - they then bite humans to transmit the disease - no transovarian transmission (don’t confuse babesiosis with Lyme disease, a bacterial disease, also transmitted by deer ticks) meadow vole Human deer tick
Babesia microti PATHOLOGY - ___________________________________________________ Immunocompromised persons are at greatest risk: ________________________________________________________ ________________________________________________________ TREATMENT – Babesia microti in human rbc’s
The Coccidians – Chapter 8 • Coccidians are members of the Phylum Apicomplexa that __________________________________(not rbc’s) of the vertebrate host. • There are several species of medical and veterinary importance. • Cryptosporidium spp. • Several species of Cryptosporidium are well known as intestinal parasites of domestic animals (sheep, cattle, chickens, & turkeys) causing the disease ____________________________________________. • 3 species are now recognized: • Human species – Cryptosporidium hominis (anthroponosis) • Cattle species: • Cryptosporidium parvum (zoonosis) – affects humans and other livestock • Cryptosporidium andersoni - in cattle only (not known if zoonotic) • research at UWEC found 38% infection rate of C. parvum in dairy calves • - outbreaks occur throughout the U.S.
Cryptosporidium • Cryptosporidium was recognized as_______________________________ • recognized in AIDS patients in 1976 • ______________% of AIDS patients reported to CDC have Cryptosporidium
Cryptosporidium • This parasite has been incriminated in large outbreak of diarrhea in humans in ______________________________________________ • associated with contamination of surface water in Lake Michigan used for drinking • due to Cryptosporidium ____________________ – likely from a sewer contamination of drinking water • one of 2 water purification plants was contaminated, and treated water showed high turbidity levels. • numbers of cases – • cost -
Cryptosporidium parvum _____________ on the surface of small intestinal cells
Oocysts of Cryptosporidium Each oocyst contains 4 sporozoites that attach to surface of small intestinal cells unstained acid red stain Oocysts from cattle feces – oocysts are 4-5 µm in diameter
Cryptosporidium • MOST Cases of Cryptosporidiosis are a ______________________________as human infections arise from infections in young cattle • oocysts in cattle feces typically contaminate surface water used for drinking • PATHOLOGY: • (1) In immunocompetent (normal) humans - • (2) In AIDS patients and immunocompromised persons - • TREATMENT -
Cyclospora • First human cases reported in 1979 • Major outbreak of Cyclosporacayetanensis occurred in New York in 1996 • 1400 cases of diarrhea reported • cause ? • Several other cases have implicated _______________________________ • ______________________________________________________ • – these have been exposed to fecal contamination
Cyclospora • LIFE CYCLE is similar to Cryptosporidium: • oocysts are the infective and diagnostic stage – size is ________µm in diameter (larger that Cryptosporidium) • 4 sporozoites are released from each oocyst and penetrate cells of the small intestine - _____________________ is preferred area • parasites inside intestinal cells comparison of oocysts of Cryptosporidium and Cyclospora
Cyclospora • PATHOLOGY: • (1) in immunocompetent persons – ____________________ occurs • Symptoms usually occur in a week • Diarrhea lasts a few days or may persist for up to 6 weeks • Disease is self-limiting • (2) in immunocompromised people – diarrhea is more severe and may last several months
Isospora belli is parasitic in the ______________________________________ • Disease is primarily __________________________; cases in the U.S. are rare. • LIFE CYCLE is similar to Cryptosporidium: • Trophozoites, merozoites, & gametocytes occur in the cytoplasm of small intestinal cells (not on surface like Cryptosporidium) • Oocysts (20 -30 µm long) are released in feces (diagnostic) • Oocysts are infective to new human host via human fecal contamination. Isospora
Isospora • PATHOLOGY: • (1) in immunocompetent individuals - some are asymptomatic and others develop a ___________________________ with abdominal pain and nausea that lasts about a week (mimics _____________ and may be underreported) • (2) in immunocompromised individuals - there is a chronic off and on • diarrhea that lasts from 1 month to years • invasion and destruction of small intestinal cells causes diarrhea, abdominal pain, and nausea • __________ of AIDS patients reported to CDC had Isospora • Specific treatment is available but recurrences are common.
Eimeria tenella and Eimeria bovis Many species of Eimeria infect domestic animals and are of veterinary importance None infect humans. Two important species are: Eimeria tenella - in ________________________ Eimeria bovis - in _________________________ LIFE CYCLE – similar to that of other coccidians, but Eimera tenella and Eimeria bovis infect cells of the __________________________________ Oocysts are released in the feces of infected animals and are ingested to cause new infections.
Eimeria tenella and Eimeria bovis PATHOLOGY: E. tenella - _____________________________is affected causing fatal bloody diarrhea - highest mortality in young chickens - costs poultry farmers millions of dollars each year in losses E. bovis - cells of ________________________________ are destroyed causing a fatal bloody diarrhea in cattle All commercial feeds now contain anticoccidial drugs to prevent the disease. Again, costly to farmers. Once the disease is established, there is no effective treatment.
Toxoplasma gondii This coccidian parasite is the causative agent of _______________________ Life cycle is unusual in that it involves 2 hosts: 1. Cats are the only definitive hosts 2. Some _______________species of birds and mammals may serve as intermediate hosts. 3. Humans are ______________________________________ Toxoplasmosis is commonly transmitted from cats to humans; thus, it is a ______________________________________. Parasite has cosmopolitan distribution - recent cases have been identified in Wisconsin - is both ENZOOTIC AND ENDEMIC in Wisconsin.
Toxoplasma gondii NORMAL MAINTENANCE CYCLE - ______________________________ relationship maintains toxoplasmosis in nature. 3 METHODS OF HUMAN INFECTION: • 1. Ingestion of __________________________ via cat fecal contamination (from sandboxes, changing cat litter, etc.) • Ingestion of ___________________________ in uncooked meat (pork, lamb, beef, chicken, turkey, wild animals) • 3. Transplacental transmission of __________________________________in an infected mother across placenta to infect fetus resulting in _____________________________ Toxoplasma oocysts in cat feces
Pathology of Toxoplasma gondii • In cats - infection is asymptomatic in adult cats • acute infections caused by _____________________________________results in numerous intestinal lesions can kill kittens • In humans: • ACUTE INFECTIONS - associated with ______________________________ • _______________________________________________________________ • causes _________________________________________________________ • Symptoms are fever, headache, muscle pain, swollen lymph glands Tachyzoites occur in groups in any nucleated body cell
Pathology of Toxoplasma gondii • CHRONIC INFECTIONS - associated with ________________________________. • is often asymptomatic. • some infections may develop ______________________________________ • AIDS infections result in severe ___________________________________ (paralysis & death),retinitis, and/or myocarditis. • T. gondii has been identified in _______% of AIDS cases reported to CDC. Bradyzoites occur in a circular mass in body cells – organs commonly infected are the liver, brain, retina, and heart
Pathology of Toxoplasma gondii • CONGENITAL INFECTIONS can have 3 different pathological effects: • may be _________________________________ • may cause serious ___________________________________ • may result in ______________________________________________ • Pathology is greatest if the disease is contracted during embryonic development (i.e. the first 8 weeks after conception). Woman may not even know she is pregnant during this time. • Common defects include: • ______________________________________ • ______________________________________ • ______________________________________
Pathology of Toxoplasma gondii DIAGNOSIS – TREATMENT –
PREVENTION: A WOMEN WHO KNOWS SHE IS ___________________________ SHOULD NEVER HANDLE THE LITTERBOX OR CLEAN UP AFTER CATS. IT IS BEST NOT TO HAVE A CAT DURING CHILD-BEARING YEARS. SO GET RID OF THE ___________________________! Recent article: http://www.cnn.com/2005/HEALTH/02/09/pregnancy.catbox.ap/index.html
Pneumocystis jirovecii (formerly Pneumocystis carinii – name in text) • This parasite was originally described as a member of the Phylum Apicomplexa • it is now considered to be a ______________________, most closely related to a group of __________________________ • however, it shows many protozoan characteristics • Species name was changed in 2005 - • P. jirovecii is now human species; P. carinii is a rat species • Interesting it was first identified by ____________________________ who discovered it when working on the life cycle of ________________________ in 1909
Pneumocystis jirovecii (formerly Pneumocystis carinii – name in text) Parasites occurs in _____________________ ____________________________________ Two stages -__________________________ ____________________________________ - have been identified in infected lung tissue.
Pneumocystis jirovecii • PATHOLOGY: • 1. Parasites are _______________________________in healthy persons. (Recent study reported that >75% of children over age 4 are seropositive.) • In AIDS patients, the parasite causes severe _______________________________________________ • - Symptoms are ________________________________________________________________________________ • - This complication often is a major cause of death in AIDS patients. • - Pneumocystis occurs in _____________ of patients having AIDS
Pneumocystis jirovecii TRANSMISSION - ____________________________________ and by __________________________________ from one person to another. DIAGNOSIS – chest X-ray with pulmonary infiltration; ID organism in bronchial washings or lung biopsy TREATMENT – a variety of ___________________________________ are now available to AIDS patients