HEALTH: Defeating kala azar needs more than new treatment

Access to treatment for a killer tropical disease that affects up to half a million people annually is being jeopardized by international inattention, despite the introduction of a new combination therapy, health experts warn.

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Visceral leishmaniasis (VL), also known as kala azar, is the worst form of a disease caused by the unicellular leishmaniasis parasite, which is transmitted by sand fly bites. It leads to high fever, severe weight loss, swelling of the spleen and liver, anaemia and, if left untreated, death in up to 100 percent of patients. In terms of parasitic killers, VL comes second only to malaria.

“Over the years, there has been neglect of kala azar by pharmaceutical companies as well as funding agencies because the affected do not have purchasing power,” said Monique Wasunna, assistant research director at the Kenya Medical Research Institute and Africa head of the Drugs for Neglected Diseases initiative (DNDi).

“Labs are not interested in kala azar, unlike avian flu, for example. For instance, for TB [Tuberculosis], governments are paying for treatment but kala azar treatment relies on support from WHO, MSF [Médecins sans Frontières] and others,” said Mercè Herrero, of the World Health Organization’s Leishmaniasis National Control Programme in Ethiopia.

“Kala azar has also not been a priority even in the data surveillance by governments. In Bangladesh, for instance, there are only 7,000 reported cases per annum but they expect about 40,000.”

WHO estimates that globally about 1.5 to two million new leishmaniasis cases occur annually but only 600,000 are officially declared.

In the absence of an effective oral medication, most treatment for kala azar consists of a 30-day course of injections, a tall order in many remote areas with minimal or poorly funded health infrastructure.

In 2010, WHO recommended a new, cheaper combination therapy, one that slashes treatment time to 17 days. This is already in use in South Sudan but other endemic countries in east Africa have yet to roll it out, even if they have begun to make the necessary regulatory changes.

“Neglected diseases and patients mean that even when there are new treatments and hope, they are too far from the headlines and donor priorities to get support to governments. This is why we are calling for urgent action,” said Wasunna.

South Sudan, which gained independence in July 2011, faces other hurdles: insecurity and flooding in areas such as Jonglei State have hampered the response to recent outbreaks, says Mounir Lado, Director for Endemic Tropical Diseases Control in South Sudan’s Health Ministry.

“In Old Fangak [in Jonglei] we are using about 400 syringes a day; we need supplies and the training of health workers on diagnostic techniques and case management,” he said.

Reliable kala azar diagnosis involves aspirations from the bone marrow, lymph node or spleen, which require skilled microscopy.

At least 10,000 kala azar cases were recorded in South Sudan in 2010, with 6 percent resulting in death, he said.

Vector control is useful only under certain conditions and often requires infrastructure and vigilance beyond the capability of many endemic countries, according to WHO.

Co-infection concerns

WHO’s Herrero said another emerging concern was co-infection of kala azar and HIV.

“The two diseases are mutually reinforcing: HIV-infected people are particularly vulnerable to VL, while VL accelerates HIV replication and progression to AIDS,” states WHO. Kala azar causes lowered immunity.

The situation is exacerbated by the fact that the risk of treatment failure for kala azar is high regardless of the drug used and that all co-infected patients will relapse – and eventually die – unless given antiretroviral therapy.

“Further, co-infected patients can serve as human reservoirs, harbouring numerous parasites in their blood and becoming a source of infection for the insect vector,” warns WHO.

“The situation may soon worsen in Africa and Asia where the prevalence and detection of HIV and leishmania co-infections still are probably largely underestimated.”



Theme (s): Health & Nutrition,

[This report does not necessarily reflect the views of the United Nations]