Cyclospora cayetanensis infection in Lagos, Nigeria

Epidemiology of Cyclospora cayetanensis: A review focusing in endemic areas

Cyclospora cayetanensis is an intestinal coccidian protozoon that has emerged as an important cause of endemic or epidemic diarrhoeal illness in children and adults worldwide. Humans appear to be the only natural hosts. However, the role of animals as natural reservoirs is uncertain but of increasing concern. Human-to-human spread of the parasite occurs indirectly via the environment through oocysts in contaminated water, food or soil. In endemic areas, risk factors associated with the infection include contaminated water or food, contact with soil or animals, type of sanitation and low socioeconomic status. Infections linked to soil contact provide reasons to believe that this route of spread may be more common than realised in disadvantaged community settings. C. cayetanensis is an important cause of traveller's diarrhoea and numerous large foodborne outbreaks associated with the globalisation of the food supply and importation of fruits and vegetables from developing countries have occurred. Waterborne outbreaks have also been reported. Implementation of measures to prevent or control the spread of Cyclospora oocysts in the environment is critical. In endemic areas, the most important steps to prevent infection are improving environmental sanitation and health education. Significant gaps remain in our understanding of the epidemiology of human cyclosporiasis that highlight the need for continued research in several aspects of C. cayetanensis.

[Immigration and HIV Infection. An approximation to parasitic and viral infections]

Highly-active antiretroviral therapy is effective in reducing opportunistic infections in industrialized countries. However, opportunistic parasitic infections remain the leading cause of HIV-related mortality in developing countries. These infections can also affect HIV-positive immigrants residing in Spain, as well as HIV-infected patients traveling to low-income countries. In addition, immigrants often have viral infections caused by herpesvirus, papillomavirus and polyomavirus, which are closely related to risk behaviors and commercial sex. The present article reviews the characteristics of parasitic and viral infections in patients with HIV infection with the aim of improving understanding of this vulnerable population group.

Cyclosporiasis: an emerging public health concern around the world and in Africa

BACKGROUND

Cyclosporiasis is an emerging gastro-enteric disease caused by the coccidia protozoan Cyclospora cayetanensis. It is associated with diarrhoea among children in developing countries, in the Americas where C. cayetanensis is endemic, traveller's diarrhoea and/or food and waterborne outbreaks in the developed countries.

OBJECTIVES

The aim of this review is to highlight cyclosporiasis and its relevance to public health in East Africa and Africa at large.

METHODS

All literature on Cyclospora, C. cayetanensis, cyclosporiasis in Africa, and endemic cyclosporiasis was searched from libraries, colleagues and internet but only literature on its history, clinical presentation, epidemiology in endemic settings, and occurrence in Africa were scrutinised.

RESULTS

In Sub Saharan Africa, cyclosporiasis has been reported in at least 3 countries, including Tanzania, in East Africa, occurring in both immunocompromised and immunocompetent patients. Zoonotic species of Cyclospora have also been identified in East African primates, indicating likely endemicity of this little reported disease in the region. This can be attributed to lack of awareness in the public and medical profession concerning the disease, and therefore not routinely checked at the health centres. Cyclosporiasis is characterized by intermittent diarrhoea, and secondary conditions or sequelae such as reactive arthritis syndrome (Reiter's syndrome), have been associated with progression of the disease. Its management is based on antibiotics, an unusual scenario for a protozoa.

CONCLUSIONS

Although many aspects of this disease and its transmission remain an enigma, the situation has been rapidly changing since the disease first came to medical attention in the 1970s.

Cyclospora cayetanensis, a food- and waterborne coccidian parasite

Food- and waterborne coccidia including Cryptosporidium parvum, Cyclospora cayetanensis, Sarcocystis hominis and Sarcocystis suihominis, and Isospora belli are cyst-forming apicomplexan protozoa that cause intracellular infections, predominantly in the epithelial cells of the intestine. They are transmitted by oocysts from person-to-person by the fecal-oral route or via contaminated water or food. The most common symptom of infection is diarrhea, however, asymptomatic infections occur. Infections are associated with intestinal inflammation, with pathological lesions such as villus blunting, and abnormal function such as malabsorption. Mild-to-moderate, self-limiting diarrhea is common in healthy individuals ingesting infective stages of these organisms. However, patients with immune dysfunction can have severe intestinal injury and prolonged diarrhea. Diagnosis in many cases is made by a microscopic examination of the stool, and the use of appropriate staining techniques, but more recently molecular methods for detection are used increasingly. Effective antimicrobial treatment for prolonged infection in immunocompromised patients is available for most of these infections. These gastrointestinal coccidial pathogens have important similarities in epidemiology, disease pathogenesis, clinical manifestations, diagnosis, and treatment. Although there are many other cyst-forming coccidia of public health, veterinary and/or economic importance, discussion in this chapter will be limited to C. cayetanensis, as an important example of the group. Aspects of the biology, epidemiology, diagnosis, disease, treatment and control are considered. This parasite is considered to be an emerging pathogen. From 1990 to 2000, there were 11 foodborne outbreaks of cyclosporosis in North America that affected at least 3600 people. There are many outstanding questions regarding this parasite and under-reporting is common because general diagnostic methods for intestinal parasites are inadequate for detection of Cyclospora.