Visceral leishmaniasis in HIV patients

Visceral leishmaniasis in HIV patients

To date this co-infection is reported from 35 countries. The first case reported was from Spain in late 1980s, with increasing incidence until the introduction of ART. In 1980s and 1990s, 90% of the HIV co-infected VL cases were reported from Southern Europe. In Bihar, India, prevalence of HIV among VL cases increased from 0.88% in 2000 to 2.18% in 2006.

Prevalence of HIV among VL cases in Northwest Ethiopia was reported as high as 41% among admitted VL cases (2003-5).  With the decreasing HIV prevalence, the HIV coinfection rate among VL patients has also decreased in the last couple of years but is still much higher than that of the general population (10-20%).

Why is VL in HIV patients special?

Effect of HIV on VL

Epidemiological – the incidence of VL has increased in the era of HIV. As is known all infection with leishmania parasite does not lead to disease. It is only less than 10% of those infected that develop the disease. HIV has increased the disease expression rate by 100 to 2000 fold. This was noticed in the Southern European countries in the early periods of the HIV outbreak. The introduction and scale up of ART subsequently has decreased the incidence.

Clinical – Atypical clinical manifestations are common with HIV co-infection. In addition to the usual reticuloendothelial system organs, manifestations may be seen in other system organs. There are reports of leishmania affecting all levels of the gastrointestinal system from oral mucosa down upto the rectum. Renal, cardiac and pulmonary dissemination of the disease and superinfection on other pathology such as different skin disorders and malignancies are reported. Diagnosis needs early suspicion and subjecting specimens from lesions for biopsy and microscopy examination.

Diagnosis – Antibody detection based assays perform poorly. This may depend on the timing of VL infection with respect to the HIV infection. While those who are profoundly immunosuppressed from long duration of HIV infection may not mount adequate antibody levels to be detected resulting in false negative results. Thus, the antibody based diagnostics are less useful in the presence of HIV co-infection.

Parasite – The less virulent forms of leishmania parasites (e.g. the dermotrophic ones) can cause visceral disease in HIV co-infected patients.

Treatment – Most studies showed an initial cure (by one month) rate of about 50% with little differences between existing regimens. About one third of them require prolonged treatment for two or more months. Adverse events related to the drugs occur frequently. After cure, 60-70% of them relapse within the first year of treatment. Post Kala-azar dermal leishmaniasis rate is higher among HIV co-infected patients.

Effect of VL on HIV

During VL infection, there is upregulation of CXCR4 and CCR5 that serve as co-receptors for the HIV virus. This facilitates the viral replication and accelerates HIV disease progression and the treatment outcome deteriorates.

Impact of the double infection

The persistent parasitemia in HIV co-infected VL patients makes them potential reservoirs and source of infection in the community. With the high treatment failure rate, need for prolonged treatment and treatment failure, these patients are also potentially risk groups for emergence of drug resistance. In general, the double infection leads to profound immunosuppression and failure of the treatment for both the VL as well as the HIV. Patients remain immune suppressed and this predisposes to other opportunistic infections and death.