Читать книгу Parasitology - Alan Gunn - Страница 108

Post kala‐azar dermal leishmaniasis (PKDL) is a condition that is usually associated with L. donovani and develops as sequel to visceral leishmaniasis in 2.5–20% of cases (hence ‘post‐kala‐azar’). It may manifest itself anything from immediately afterwards to several years following the condition. It is characterised by the development of nodules and/or macules that can be extensive and cover any area of the body and may be mistaken for leprosy. The nodules are irregular raised masses on the skin surface whilst macules (Latin macula = blemish or small spot) are flat discoloured areas on the skin surface. These regions contain numerous amastigotes, and if they occur on exposed parts of the body, they are a ready source of infection for sandflies. The identification and treatment of patients suffering from PKDL is therefore an important part of any control programme. There are marked differences the occurrence and development of PKDL between countries, which suggests that host, and/or parasite factors may be important in whether it develops. For example, most cases of PKDL (~50%) occur in the Sudan and the condition tends to develop more rapidly there than in India.

Some workers consider that the development of PKDL is associated with the incomplete or inefficient treatment of visceral leishmaniasis following treatment with the drugs sodium stibogluconate and pentamidine. However, PKDL may also occur after treatment with miltefosine. In India, Das et al. (2009) found about 20% of PKDL cases occurred in people for whom there was no record of either visceral leishmaniasis or the prescription of the drugs used to treat it. However, these people tested positive for L. donovani and therefore carried an asymptomatic infection.