KATMANDU — Nepal, the “country of a thousand gods,” presents a sad paradox. Endowed with exquisite beauty, it is at the same time home to a series of infectious diseases that take a heavy toll on its population. Perhaps the less known among them, and the most neglected, is kala azar. The name literally means “black sickness” because of the darkened skin of some patients.
Kala azar is the Mogul vernacular name of visceral leishmaniasis, a disease fatal if not treated, which affects annually 500,000 people in 69 countries, putting at risk a population of 350 million. Ninety percent of the cases occur in Bangladesh, India, Nepal and Sudan, and it has also been reported in 12 veterans of the Persian Gulf War, who apparently contracted the disease while in Saudi Arabia.
Kala azar, characterized by an enlarged liver, irregular fever and anemia, results from infection with a parasite transmitted by a sand fly that uses humans as a reservoir. Kala azar is not uniformly distributed in affected areas. It normally exists in areas of drought, famine and densely populated villages with poor or no sanitation. Among those most commonly affected are older children and young adults of both sexes, especially males.
Kala azar was originally reported in India in 1824 from where it spread to Bangladesh and Nepal. In Nepal it was first reported in 1980. Since then, 21,612 people have been affected. The DDT used in India by the National Malaria Eradication Program in the 1940s ravaged the sand fly population and interrupted the transmission of kala azar. By the mid-1950s no new cases of kala azar had been recorded in India, and in the mid-1960s kala azar had become an almost forgotten disease.
However, when the national malaria campaign was interrupted, kala azar reappeared in 1970 in the Indian village of Vaishali, Bihar State.
Vaishali is where Buddha is said to have experienced his last enlightenment before dying. It also has the dubious distinction of being the place where kala azar reclaimed its territory. In the late 1970s, the disease crossed the river and appeared in Bangladesh; shortly thereafter it entered Terai, the agricultural area in Nepal that borders Bihar State. Kala azar is now endemic in 13 Nepalese districts in this border area.
Dr. Panduka Wijeyaratne, resident adviser for the Environmental Health Project in Nepal (funded by USAID), is an expert on kala azar. For the past several years, this project has carried out a series of actions aimed at reducing the threat from this disease. I recently met with him in Katmandu.
“What we have already seen is only the tip of the iceberg,” he told me, “because below are many asymptomatic cases, some of which will become symptomatic, particularly among the poor.”
Kala azar thrives under bad conditions. It affects those of low socioeconomic levels in households where hygiene and sanitation are poor, circumstances that favor the spreading and multiplication of the sandfly vector of the disease. Efforts to treat the disease cannot ignore that globalization and trade, combined with increasing socioeconomic disparities, have led to increased international migration.
India, Nepal and Bangladesh are examples of countries with porous borders and a frequently migrant population. Migrants are particularly vulnerable, as their movements entail the risks of propagating communicable diseases and infections such as HIV/AIDS, tuberculosis, malaria and kala azar. An oral drug, miltefosine, presently being tested at the B.P. Koirala Institute of Health Sciences in Dharan, Nepal, offers hope of replacing the lengthy and painful injectable treatments used so far.
Dr. Suman Rijal, additional professor in charge of tropical diseases at the B.P. Koirala Institute of Health Sciences in Dharan, Nepal, told me: “Kala azar is a social disease. If you improve the social and economic conditions of the people you’ll do a lot toward controlling it.”
Dr. Vijay Kumar Singh, a senior physician at Janakpur Zonal Hospital, is eager to communicate his experience dealing with kala azar for more than 20 years during which he has treated more than a thousand patients. I asked him if kala azar can be controlled and eventually eliminated.
“Yes, it can,” he said, “But we have to think about a long-term, 10-year effort. What is necessary is a complementary set of activities including early detection at the community level, prompt treatment, regular followup and completion of treatment, synchronization of activities between India and Nepal, and continuing political will.”