Monograph

Mon, 01/24/2011 - 16:12 — Anonyme

definition:

Parasitic disease transmitted to humans, cosmopolitan, closely correlated to hygiene conditions, it is most often associated to developing countries.

Situation in America:

This disease is reported in Central and South America (Mexico, Guatemala, Ecuador, Honduras, Bolivia, Peru, Brazil), Africa (Senegal, Benin, Cote d'Ivoire, Togo, Ghana, Burkina Faso, Nigeria, DRC, Cameroon, Burundi, Kenya, Rwanda, Tanzania, Uganda, Mozambique, Zimbabwe, South Africa), Indian Ocean (Madagascar, Reunion Island), Asia (Indonesia, India, Vietnam, Cambodia, Laos, Korea China, Nepal, Mongolia, Philippines, Myanmar). Cysticercosis has been eradicated in Europe in the early twentieth century, except in some countries of Eastern Europe and Portugal.

Susceptible species:

Mainly cattle, swine and humans. In reality, all vertebrates are potentially susceptible species.

Etiological agent:

Tapeworm, taenia saginata and taenia solium worms are flat or Cestodes belonging to Platyhelminthes.

The larval stages of these two worms are called cysticerci, they are hosted by intermediate hosts, cattle for taenia saginata and taenia solium to pigs. Both larval stages are infective to humans (definitive host) where they determine the taeniasis.

However, it is possible for man to become an intermediate host (only for taenia solium), cysticerci then cause cysticercosis.

Methods of transmission

Source:

Pork miser, contaminated faeces, contaminated food or water.

Transmission:

Infection of pigs is facilitated by its habits dung, low condition of hygiene especially systems precarious farm where pigs have easy access to human faeces.

The man contracted cysticercosis by ingesting cysticerci contained in meat raw or undercooked pork.

Method of contamination:

Ingestion of contaminated food or eggs.

Symptoms:

The cysticerci are found in all organs of the human or animal. However, they appear more often located in subcutaneous tissues, muscles, the eyes and brain (neurocysticercosis).

In Pigs:

Most often asymptomatic, the disease can cause changes in appetite (bulimia, anorexia) in animals as well as abdominal pain with diarrhea and / or vomiting.

In humans:

The symptoms caused by cysticerci are diverse depending on the location and density of pathogens. The cysticerci are present in tissues such as cysts, fluid-filled thin-walled and translucent. To complete its life cycle, the cysticerci have to survive in the tissue of its host several weeks or months. Morphologically, there are four stages of development and regression of cysticerci:

- Stadium where the vesicular cysticerci are viable, this stage produces only little inflammatory response from the host,

- Colloidal vesicular stage corresponding to necrosis of the parasite associated with an inflammatory process,

- Granular nodular stage: the cyst shrinks, its content tends to be mineralized and seems granular
- Nodular calcified stage: the granular material of the previous stage becomes completely mineralized. The nodular calcified cysticercus is small, about a third or a quarter of the cysticercus vesicular.

Diagnostics

Clinical diagnosis:

Human cysticercosis:

The diagnosis of carriers of Taenia solium is mostly limited to the presence of eggs and / or proglottids in feces by conventional stool examination. However, more sensitive immunological methods have been recently developed like ELISA for detection of copro-antigens and immunoblotting. Nowadays, the specific diagnosis of taeniasis is possible through the PCR technique.

The EITB, ELISA, immunoelectrophoresis, indirect hemagglutination are widely used for serological diagnosis of human cysticercosis. ELISA tests based on monoclonal antibodies developed for detection of circulating antigens of Taenia saginata cysticercosis in cattle were found in the same way, performing to detect human cysticercosis. These tests have the advantage of differentiating between active and past infections.

Swine cysticercosis:

The diagnosis of carriers of Taenia solium is mostly limited to the presence of eggs and / or proglottids. Another technique is used by the tongue inspection, it is to feel and to identify Taenia solium cyst on the underside of the tongue. It is possible to inspect the carcasses of meat for a search cysts caused by this worm.

Treatment:

There is no treatment in pigs. In humans, two cestocides treatments can be administered:

- Praziquantel (Biltricide ®), a tablet scored Quad, dosed at 600 mg. The dosage is 50 mg / kg / d in 2 doses, cures in 15 days.

- Albendazole (Zentel ®), presented in 200 mg tablets or oral suspension containing 100 mg per teaspoon (20 ml vial containing 400 mg of albendazole). The dosage is 15 mg / kg / d in cycles of 15 days.

Prophylaxis:

Sanitary prophylaxis

- Remove the source of human infection by a systematic search of eggs and rings, test routine treatment, latrine and advice on food hygiene.

- Monitoring of pigs looking for cysticerci at slaughter, prohibition of stray pigs and improved farming techniques.

Vaccines:

Vaccines developed using antigens of Taenia solium.