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Chpt. 23 For Students Ppt

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Chagas Disease Also known as ``American trypanosomiasis`` Definition of Chagas disease: Chagas disease is an illness spread by insects. It is common in South and Central America. Chagas disease is caused by Trypanosoma cruzi, a parasite related to the African trypanosome, that causes sleeping sickness. It is spread by reduvid bugs and is one of the major health problems in South America. Due to immigration, the disease also affects people in the United States. Chagas named it for the Epidemiologist Oswaldo Cruz
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Page 1: Chpt. 23 For Students Ppt

Chagas Disease• Also known as ``American trypanosomiasis``

• Definition of Chagas disease:

Chagas disease is an illness spread by insects. It is common in South and Central America.

Chagas disease is caused by Trypanosoma cruzi, a parasite related to the African trypanosome, that causes sleeping sickness.

It is spread by reduvid bugs and is one of the major health problems in South America. Due to immigration, the disease also affects people in the United States.

• Chagas named it for the Epidemiologist Oswaldo Cruz

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Chagas Disease• Occurs in several different countries-• Southern Texas, Mexico, Central America and parts of South

America.• Infects 40% to 50% in rural areas in South America.• An estimate of 100,000 infected immigrants carry this disease

into the United States.• T. cruzi is carried in several wild animals and by the reduviid

bug (kissing bug).

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Trypanosoma Cruzi

• This causative agent is carried in several wild animals…rodents, opposums and armadillos.

• And also by the arthropod vector which is the reduviid bug (kissing bug).

• This kissing bug lives in cracks, crevices of mud or stone huts.

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Trypanosomes (flagellated protozoan)

• Grows in the gut of the bug.• Is passed on, when the bug defecates while feeding (sucking

blood) on humans or animals.• The bitten host then rub the bug feces into the bite wound or

abrasions and eyes unconsciously and gets infected by this disease.

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Life cycle of Chagas Disease

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Treating Chagas Disease

• Can be very difficult to treat if chronic stage progresses.• Trypanosome multiplies intracellularly and is difficult to reach

chemotherapeutically.• Drugs currentlyavailable, such as nifurtimox have toxic side

effects and have low effectiveness.

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Test showing T. Cruzi present• T. cruzi trypomastigote in

cerebrospinal fluid (CSF) stained with Giemsa.

• T. cruzi amastigotes in heart tissue. The section is stained with hematoxylin and eosin (H & E).

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Toxoplasmosis• Surprisingly cats are the reservoir for this disease.

Toxoplasmosis is a disease of the blood and the lymphatic vessels.

• It is caused by a protozoan called T. Gondii. • T. Gondii is a single celled spore forming protozoan or

parasite. It can confuse you at times because it mimics the malarial parasite.

• Being that the disease resigns in cats it does not affect the cat at all. The cat is T. Gondii’s source of energy, it is what keeps the disease growing and the protozoan working to progress more and more.

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What You Should Know!!!• More than 60 million people are walking around with the parasite

toxoplasmosis and very few do not show signs of illness because their immune system is keeping the parasite from causing illness

• To keep the disease latent in cats avoid feeding the cat raw meat, change their litter boxes frequently but with gloves to get rid of parasites before they become infectious

• Avoid handling stray cats or kittens• Keeps cats indoors as much as possible• Feed cats dry canned foods to prevent chances of triggering the parasite

to cause infection • After the infection is excited cats pass it into their feces everyday• The parasites mature within two to five days with yourself once infected• There is no treatment to prevent the passing of the parasite or to keep it

from triggering within the cat and causing infection

Important- There is a cure as long as you have not reached the chronic bradyzoite stage which is toxic and very fatal

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Types of Malaria

• Four Types of Malaria–Plasmodium falciparum

malaria: life-threatening and It can be fatal within a few hours of the first symptoms.

–P. vivax, P. malariae, and P. ovale: are generally less serious and are not life-threatening.

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Cause

• Malaria is caused by a parasite that is transmitted from one human to another by the bite of infected Anopheles mosquitoes.

• In humans, the parasites (called sporozoites) migrate to the liver where they mature and release another form, the merozoites. These enter the bloodstream and infect the red blood cells.

• The parasites multiply inside the red blood cells, which then rupture within 48 to 72 hours, infecting more red blood cells.

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Cause• The first symptoms usually occur 10 days

to 4 weeks after infection, though they can appear as early as 8 days or as long as a year later. Then the symptoms occur in cycles of 48 to 72 hours.

• Malaria can also be transmitted congenitally (from a mother to her unborn baby) and by blood transfusions.

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Diagnosis

• Most do blood smear on a microscope slide that is stained (Giemsa stain) to show the parasites inside red blood cells.

• RDT (rapid diagnostic tests)• polymerase chain reaction (PCR)

tests: is a method to analyze a short sequence of DNA or RNA.

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Treatment

• The correct drugs for each type of malaria must be prescribed by a doctor who is familiar with malaria treatment protocols.

• Currently, there is no vaccine available for malaria, but researchers are trying to develop one.

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Leishmaniasis

• Leishmaniasis is a widespread and complex disease that exhibits several forms

• Leishmaniasis is transmitted by the bite of a sand fly

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-These insects are smaller than mosquitoes

-They can actually fit through the mesh of standard netting

-The infective form is in the saliva of the insect

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• A number of cases of Leishmaniasis, mostly cutaneous, occurred among troops fighting in the Persian Gulf War

• Occasional cases of Leishmaniasis are beginning to appear in HIV-infected persons

• Leishmaniasis protozoan pathogens are of about 20 different species and can be categorized into 3 groups:- Leishmania Donovani- Leishmania Tropica- Leishmania Braziliensis

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L. Donovani (Visceral Leishmaniasis)

• This protozoa multiplies in the liver and spleen, causing organs to enlarge greatly.

• Eventually, kidney function is also lost as these organs are invaded.

• Leishmaniasis is often fatal and without proper treatment can result into death within 1-2 years

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L. Tropica (Cutaneous Leishmaniasis)

• Leishmania Tropica is a cutaneous form of leishmaniasis and is sometimes called the orienatal sore.

• A papule appears at the bite site after a few weeks of incubation.

• The papule ulcerates and, after healing, leaves a prominent scar

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Leishmania Braziliensis• Also known as Mucocutaneous Leishmaniasis• Mostly found in Yucatan Peninsula of Mexico

and rainforests areas of central and South America.

•Affects mucous membrane as well as skin.

Causes disfiguring destruction of tissues of the nose, mouth, and upper throat.

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Treatment

• The primary treatment is an injection of sodium stibogluconate, that contain a toxic metal antimony.

• An orally administered Miltefosine, has been shown to be very effective.

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Life cycle


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