Resources Causal Agent The trematodes Fasciola hepatica also known as the common liver fluke or the sheep liver fluke and Fasciola gigantica are large liver flukes F. Although F. These forms usually have intermediate morphologic characteristics e. Further research into the nature and origin of these forms is ongoing. Life Cycle Immature eggs are discharged in the biliary ducts and passed in the stool.
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Mechanism[ edit ] The development of infection in definitive host is divided into two phases: the parenchymal migratory phase and the biliary phase. After the penetration of the intestine, flukes migrate within the abdominal cavity and penetrate the liver or other organs.
The second phase the biliary phase begins when parasites enter the biliary ducts of the liver. In biliary ducts, flukes mature, feed on blood, and produce eggs. Hypertrophy of biliar ducts associated with obstruction of the lumen occurs as a result of tissue damage. Resistance to infection[ edit ] Mechanisms of resistance have been studied by several authors in different animal species.
These studies may help to better understand the immune response to F. It has been established that cattle acquire resistance to challenge infection with F. In addition antibody concentration quickly drops post treatment and no antibodies are present one year after treatment, which makes it a very good diagnostic method. Coprological examinations of stool alone are generally not adequate because infected humans have important clinical presentations long before eggs are found in the stools.
Moreover, in many human infections, the fluke eggs are often not found in the faeces, even after multiple faecal examinations. These immunological tests are based on detection of species-specific antibodies from sera. In addition, biochemical and haematological examinations of human sera support the exact diagnosis eosinophilia, elevation of liver enzymes.
Ultrasonography and xray of the abdominal cavity, biopsy of liver, and gallbladder punctuate can also be used ref: US-guided gallbladder aspiration: a new diagnostic method for biliary fascioliasis.
Kabaalioglu, A. Apaydin, T. Sindel, E. False fasciolosis pseudofasciolosis refers to the presence of eggs in the stool resulting not from an actual infection but from recent ingestion of infected livers containing eggs. This situation with its potential for misdiagnosis can be avoided by having the patient follow a liver-free diet several days before a repeat stool examination.
However, clinical signs, biochemical and haematological profile, season, climate conditions, epidemiology situation, and examinations of snails must be considered. Moreover, the fluke eggs are detectable in faeces 8—12 weeks post-infection. In spite of that fact, faecal examination is still the only used diagnostic tool in some countries. While coprological diagnosis of fasciolosis is possible from 8- to week post-infection WPI , F.
Prevention[ edit ] In some areas special control programs are in place or have been planned. Individual people can protect themselves by not eating raw watercress and other water plants, especially from endemic grazing areas. The drug of choice in the treatment of fasciolosis is triclabendazole , a member of the benzimidazole family of anthelmintics.
Resistance of F. Triclabendazole is effective at killing flukes of any age, but only those that cause acute infections; flukes that have remained in the body for long periods of time are becoming resistant to this drug.
For example, in European countries that have large numbers of sheep, computerized systems predict when fascioliasis is most likely to make the biggest impact on sheep populations and how many sheep will most likely be affected. The predictions are dependent on guessing when environmental conditions that are most conducive to parasite multiplication will occur, such as amount of rainfall, evapotranspiration, and the ratio of wet to dry days in a particular month.
Fasciolosis occurs only in areas where suitable conditions for intermediate hosts exist. Studies carried out in recent years have shown human fasciolosis to be an important public health problem. The incidence of human cases has been increasing in 51 countries of the five continents. High prevalences in humans are not necessarily found in areas where fasciolosis is a great veterinary problem.
For instance, in South America, hyperendemics and mesoendemics are found in Bolivia and Peru where the veterinary problem is less important, while in countries such as Uruguay, Argentina and Chile, human fasciolosis is only sporadic or hypoendemic.
A total of cases of human fasciolosis were recorded from nine French hospitals from to The prevalence of the disease was serologically found to be 3. Americas[ edit ] In North America, the disease is very sporadic.
In Mexico, 53 cases have been reported. In Central America, fasciolosis is a human health problem in the Caribbean islands, especially in zones of Puerto Rico and Cuba. These Andean countries are considered to be the area with the highest prevalence of human fasciolosis in the world. Well-known human hyperendemic areas are localized predominately in the high plain called altiplano. Africa[ edit ] In Africa, human cases of fasciolosis, except in northern parts, have not been frequently reported.
The highest prevalence was recorded in Egypt where the disease is distributed in communities living in the Nile Delta. It was mentioned that more than 10, human cases were detected in Iran. In eastern Asia, human fasciolosis appears to be sporadic. Few cases were documented in Japan, Koreas, Vietnam, and Thailand. In New Zealand, F. Drugs differ in their efficacy, mode of action, price, and viability.
Fasciolicides drugs against Fasciola spp. Triclabendazole is used in control of fasciolosis of livestock in many countries. Nevertheless, long-term veterinary use of triclabendazole has caused appearance of resistance in F. In animals, triclabendazole resistance was first described in Australia,  later in Ireland  and Scotland  and more recently in the Netherlands. Recently, a new fasciolicide was successfully tested in naturally and experimentally infected cattle in Mexico.
They must be treated forthwith to prevent complications with surra and hemorrhagic septicemia diseases. Surra already affected all barangays of the Surallah town.
Parasites - Fascioliasis (Fasciola Infection)