Toxoplasmose chez les patients immunodéprimés. Apport à la connaissance de l'infection toxoplasmique

Immunology of Toxoplasma gondii

Toxoplasma gondii is an obligate intracellular parasite. Following oral infection the parasite crosses the intestinal epithelial barrier to disseminate throughout the body and establish latent infection in central nervous tissues. The clinical presentation ranges from asymptomatic to severe neurological disorders in immunocompromised individuals. Since the clinical presentation is diverse and depends, among other factors, on the immune status of the host, in the present review, we introduce parasitological, epidemiological, clinical, and molecular biological aspects of infection with T. gondii to set the stage for an in-depth discussion of host immune responses. Since immune responses in humans have not been investigated in detail the present review is exclusively referring to immune responses in experimental models of infection. Systemic and local immune responses in different models of infection are discussed, and a separate chapter introduces commonly used animal models of infection.

[Infections associated with pets]

INTRODUCTION

Domestic pets can transmit numerous infections, including bacterial, parasitic, fungal, and viral diseases. This paper reports the epidemiologic, clinical, therapeutic and prophylactic data of these zoonoses.

CURRENT KNOWLEDGE AND KEY POINTS

The routes of transmission are various. Bites and scratches are the most common health hazards and result in localized infections. Pasteurellosis, various aerobic and anaerobic infections, and cat-scratch disease are predominant. Bites are treated by cleaning the wound, rabies and tetanus prophylaxis, and the appropriate use of antibiotics. Other infections are transmitted through cutaneous, mucous, digestive or respiratory routes, by direct contact with the pets, excreta, or by arthropods. The most common are gastrointestinal (campylobacter, salmonella, yersinia, parasites, etc), dermatologic (dermatophytoses, scabies, cutaneous larva migraines, etc.), respiratory (psittacosis, etc.), and multisystemic (toxoplasmosis, toxocariasis, leishmaniosis). Certain people are at high risk for diverse diseases: small children (toxocariasis, helminthiasis), pregnant women (toxoplasmosis), and immunodeficient patients (cryptosporidiosis, salmonellosis, systemic pasteurellosis). These infectious diseases can be partly prevented by avoiding contact with diseased animals, and by washing the hands following exposure to pets or pet-derived excreta. Specific vaccines for humans and pets, as well as worming pets regularly, form an important part of the prevention. Veterinarians must discourage the keeping of wild or exotic animals as pets.

FUTURE PROSPECTS AND PROJECTS

National health survey institutions and new communication systems can improve our knowledge about the real epidemiology of pet-transmitted zoonoses.