Patients Treated for Visceral Leishmaniasis Can Still Transmit Disease, Study Reveals

Geneva / New Delhi – July 22, 2019 – The results of an innovative study on "infectivity" conducted by the Drug Initiative for Neglected Diseases (DNDI) and the International Center for Diarrheal Disease Research in Bangladesh (icddr, b) confirm that people successfully treated for visceral leishmaniasis in South Asia can still infect others if they develop a skin condition known as post-kala-azar cutaneous leishmaniasis (PKDL). The results were published in Clinical Infectious Diseases this week.

Patients can develop cutaneous lesions in the form of rashes and nodules, usually six to one year after the end of treatment for visceral leishmaniasis, a deadly parasitic disease transmitted by sandflies, also called kala-azar or fever black. PKDL lesions contain the same parasite that causes kala-azar. The objective of the study was to determine whether skin parasites of PKDL patients could be transmitted to sandflies that transmit kala-azar.

"This is the largest study of its kind so far." Until now, information on the role of PKDL was scarce and scattered over several decades of different research initiatives. said Dr. Jorge Alvar, Senior Counselor for Leishmaniasis at DND.I and co-principal investigator of the study. "The results show unequivocally that PKDL is of paramount importance for the maintenance of disease transmission between epidemics."

As part of the trial, patients with PKDL were stung by laboratory-cultured sandflies (free from infection) by dipping their hands in a cage for 15 minutes containing female and female sand flies. The sandflies were then badyzed for kala-azar parasites.

The results showed that nearly 60% of the 47 PKDL patients participating in the study were transmitting parasites to sandflies. This means that the insects could then infect someone else.

"Because PKDL is not fatal, it has been largely ignored by public health efforts and many scientific questions regarding its role have not been resolved," said Dr. Dinesh Mondal, researcher Main to the icddr, b and principal investigator of the study. "While these new findings do not answer all of our questions, they nonetheless show that early treatment of PKDL patients will be an essential part of any public health strategy and elimination of leishmaniasis."

People with PKDL sometimes remain untreated for a long time. The transmission of the disease could therefore occur even when the kala-azar is controlled and only a small number is reported.

"Great progress has been made in controlling kala azar in South Asia, but this study shows that we must now engage in active detection of PKDL cases and provide timely treatment as an integral part of the control and of the elimination of kala-azar, "said the minister. Dr. Suman Rijal, Director of DNDI Regional Office in India. "The PKDL needs to be addressed in order to continue the elimination, otherwise we risk compromising our previous successes."

Forty-seven PKDL patients and 15 patients with kala-azar were tested for xenodiagnosis. The results showed that, depending on the type of PKDL lesion, 35% (9/26) of macular 86% (18/21) nodular PKDL patients in the study were transmitting parasites to sandflies (p 0.0009). , while 67% of the 10/15 kala-azar control patients did so. This means that insects biting the skin of a patient with PKDL could then infect someone else.

DNDI is currently preparing a similar study in Sudan. DNDI is also conducting clinical trials to test two treatment regimens in patients with PDT in South and East Africa, with the goal of making treatments simpler, safer, and more effective.

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A non-profit research and development organization, DNDI is working to deliver new treatments to neglected patients, to those suffering from Chagas disease, sleeping sickness (African human trypanosomiasis), leishmaniasis, filarial infections, mycetoma, pediatric HIV and HIV / AIDS. Hepatitis C. Since its inception in 2003, DNDI has provided eight new treatments to date, including new drug combinations for kala-azar, two fixed-dose antimalarial drugs, and DNDIThe first new and successful chemical entity, fexinidazole, was approved in 2018 for the treatment of both stages of sleeping sickness.

Manisha Sharma

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Moyette Gibbons

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Ilan Moss

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