Introduction
Visceral leishmaniasis is a protozoan parasitic disease caused by different Leishmania species in other geographical areas. In India, Nepal, and Sudan, visceral leishmaniasis is caused by Leishmania donovani, where humans are a reservoir. In contrast, in countries like Brazil, visceral leishmaniasis is caused by Leishmania infantum, where dogs are the reservoirs. The disease is transmitted through contaminated blood, mainly in patients with HIV infections, when the syringes are shared during drug infusion through an intravenous route. The co-infection between Leishmania and HIV infection has been reported in 35 endemic countries. Patients with HIV infections are more vulnerable to visceral leishmania disease. As a result, the visceral leishmania infection accelerates the HIV infection to replicate and progress to AIDS (Acquired Immune Deficiency Syndrome). The recurrence rate for visceral leishmania disease in patients with AIDS is high. Therefore, the asymptomatic coinfection of these two diseases should be considered a significant problem as it causes increased risk in visceral leishmania manifestations. The recurrence of this coinfection is determined by the immune response of the infected patients, mainly by the CD4+ T-lymphocyte cell count.
What Are the Symptoms of Visceral Leishmaniasis in AIDS Patients?
The clinical symptoms in AIDS patients with visceral leishmaniasis are:
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Weakness.
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Cough.
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Undernourishment.
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Weight loss.
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Gastrointestinal problems.
The classic symptoms of immunocompetent individuals are fever, pallor, and hepatosplenomegaly. This results in difficult diagnoses in patients with coinfection and other opportunistic infections.
The other main finding in patients with this coinfection comes to doctors with amastigotes (parasites formed in the infected patients) in unusual sites. The sites are gastrointestinal and oral mucosa, skin, pleura, pericardium, lymph nodes, Kaposi’s sarcoma lesions, and the respiratory tract.
How Is Visceral Leishmaniasis Diagnosed in AIDS Patients?
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Visceral leishmaniasis is mostly diagnosed in laboratories. However, parasitological diagnosis is a good alternative because of its high specificity and execution.
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In immunocompetent patients, samples were collected from bone marrow, lymph nodes, and spleen to find amastigotes under the microscope.
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The direct agglutination test and immunoblotting have better sensitivity when compared to ELISA and immunofluorescence antibody tests.
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Molecular diagnoses are very promising in immunocompromised and HIV-infected patients.
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PCR (Polymerase chain reaction) is another method to diagnose visceral leishmaniasis in HIV patients.
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The main methods used to diagnose visceral leishmaniasis in AIDS patients are:
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Microscopic examination (bone marrow aspiration) - Gemisa staining.
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DAT (Agglutination serological test).
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Rk39 rapid test.
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ELISA.
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IFAT and PCR.
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What Are the Treatments for Visceral Leishmaniasis in AIDS Patients?
The therapeutic approach for visceral leishmaniasis in AIDS patients is quite challenging. The major issues are the increasing resistance of most available drugs, pentavalent antimonial compounds, high relapse rate, high treatment failure, and toxicity.
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Pentavalent Antimonial Compounds: Pentavalent antimonial compoundshave been used to treat visceral leishmaniasis since the 1940s. These drugs are mainly used in areas where amphotericin B is unavailable and unaffordable. The main disadvantage of this drug is that it shows an increased toxicity rate, manifested as severe vomiting, arrhythmia, and pancreatitis.
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Amphotericin (Amphotericin B Deoxycholate/Liposomal/Lipid Formulations): The drug liposomal amphotericin B contains amphotericin B with cholesterol and phospholipids for better stability in blood and macrophages, leading to more effective drug levels and penetration. Amphotericin B is the major drug for better outcomes in AIDS patients with visceral leishmaniasis. The main adverse effects of this drug are highly toxic to endothelial cells, thrombophlebitis during infusion, headache, fever, myalgia, dose-dependent, chills, emesis, arthralgia, hypotension, etc.
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Miltefosine: Miltefosine is the only available oral drug to treat leishmaniasis. The main disadvantage of this drug is teratogenicity and gastrointestinal side effects such as vomiting, diarrhea, etc.
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Antibiotics: The other drug used for the treatment of visceral leishmaniasis is paromomycin, which is an antibiotic drug. However, it is used less commonly due to poor absorption and intramuscular route administration.
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Combined Therapy: Due to frequent treatment failures among HIV-infected patients, there is a need for alternative therapies. A broad spectrum of drugs has been used in HIV-related visceral leishmaniasis, such as liposomal amphotericin B, pentamidine, pentavalent antimonial, allopurinol, aminosidine, interferons, ketoconazole, allopurinol alone or in combination with azole compounds. Liposomal amphotericin B is used for treating HIV-infected visceral leishmaniasis as it gives promising results.
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Secondary Prophylaxis: The high relapse rate of AIDS-related visceral leishmaniasis has led to the use of secondary prophylaxis. Liposomal amphotericin B, allopurinol, antimonials, pentamidine, and azole compounds have been used as prophylactic drugs in HIV-infected individuals. The routine use of secondary prophylaxis seems advisable for patients with AIDS-related visceral leishmaniasis as there is an increased relapse rate in patients receiving no prophylaxis than prophylaxis.
Will Visceral Leishmaniasis in AIDS Patients Occur Again After Treating It?
One of the most outstanding features of HIV-associated visceral leishmaniasis is its tendency to relapse. Unfortunately, some patients followed a chronic course with multiple relapses despite treatment with multiple drugs and various regimens of secondary prophylaxis.
The clinical presentation and the sensitivity of diagnostic procedures in visceral leishmaniasis seem comparable to those of initial episodes. In such cases of relapse, secondary prophylaxis is the major treatment choice.
What Is the Prognosis of Visceral Leishmaniasis in AIDS Patients?
Visceral leishmaniasis contributes to poor prognosis in AIDS patients by causing immunosuppression independent of HIV or stimulating HIV replication. As a result, HIV-associated visceral leishmaniasis patients have a higher relapse, mortality rates, and shortened life. However, the new antiretroviral therapies have given AIDS-related visceral leishmaniasis patients a good prognosis.
Conclusion
Visceral leishmaniasis has become a common complication among AIDS patients living in endemic areas, where it behaves as an opportunistic infection in this population. Although new antiretroviral therapy has begun to change the epidemiology and prognosis of AIDS leishmaniasis, there is a need for improved diagnostic tests to detect the disease and new drugs that are more effective and less toxic for the treatment and prophylaxis of this infection. In addition, a faster approach of the patients to the disease helps in the correct treatment and better prognosis.
