Relapse

Relapse is when VL occurs in a patient who was treated and declared cured of VL before. In immunocompetent host relapse rate is less than 5%. In immune compromised people (such as patients with HIV, cancer, or immunosuppressive therapy) the relapse rate within one year of treatment reaches up to 70%.  Most relapses occur within 3-9 months post treatment. Successive relapses become less typical, and less acute. Achieving cure becomes difficult with more frequent relapses.

Treatment of relapse – All available antileishmania drugs are poorly efficacious in relapse treatment.  The treatment options are:

-        Repeat the initial regimen

-        Change the regimen to available alternative

-        Use combination therapy

Patients need to be evaluated with a test of cure at the end of their treatment and decision has to be made on the need for extension of treatment. Frequently relapsing patients can go into a chronic disease state with serial relapses. They will be exposed for several drugs and also for prolonged period. They can be riskgroups for drug resistance development and also act as reservoirs in anthroponotic transmission regions.

Possible treatment interventions to be studied for such patients include adjuvant immunotherapy, IFN-gamma, recombinant human granulocyte macrophage colony stimulating factor.

While ART helps to prolong the time to relapse, it does not totally avoid it. Secondary prophylaxis can also help to decrease relapse. Secondary prophylaxis has to be started after demonstrating negative parasite on test of cure.

References:
Cota G F, et al. Predictors of visceral leishmaniasis relapse in HIV infected patients: a systematic review, Plos NTD 5(6), 2011
Diro E, et al High Parasitological Failure Rate of Visceral Leishmaniasis to Sodium Stibogluconate among HIV Co-infected Adults in Ethiopia. PLoSNTD. 2014 May 22;8(5)