Health specialist Lucy Palmer explains how breakthrough advances in diagnosis and treatment are helping governments to improve control of visceral leishmaniasis (VL), a neglected tropical disease (NTD) that thrives in the world’s very poorest communities.
The World Health Organization (WHO) and Uniting to Combat Neglected Tropical Diseases recently invited their global partners to Geneva to mark the fifth anniversary of their campaign against NTDs. Much of the attention was on the ultimate destination: controlling, eliminating and eradicating these lesser-known afflictions. Yet, it’s also important to recognise and celebrate the milestones along the road.
In particular, the meeting offered an opportunity to reflect on recent progress in the fight against visceral leishmaniasis (also known as kala-azar or black fever). VL is probably the deadliest disease you’ve never heard of – second only to malaria in terms of parasitic killers.
The leishmania parasite is transmitted through the bites of female infected sandflies and attacks the internal organs of carriers - hence visceral. It’s almost always fatal if left untreated. Symptoms include severe fever, weight loss and fatigue, as well as swelling of the liver and spleen. This can cause a darkening of the skin around the abdomen – hence black fever.
The great news is that breakthrough advances in diagnosis and treatment have helped Nepal reduce the incidence of VL to the point where - subject to verification from the WHO - it will no longer be considered a public health problem. Bangladesh is approaching a similar stage. We are hopeful that India, the traditional stronghold in South Asia, will reach this classification in 2018.
By ‘we’, I mean the KalaCORE programme, a partnership set up to tackle VL in South Asia and East Africa. The programme is backed by £21.5m of funding from the UK’s Department for International Development (DfID). Fellow partners include the Drugs for Neglected Diseases initiative, London School of Hygiene and Tropical Medicine and Médecins Sans Frontières.[1] In partnership with the WHO, our aim is to support Nepal, Bangladesh and India in their goal to eliminate VL, and support improved control of VL in Ethiopia, Sudan and South Sudan.
In the past, health workers struggled to tackle outbreaks, as correct diagnosis typically took two months or more from the onset of symptoms. Even then, VL fevers were too often misdiagnosed. Due to a lack of awareness of the disease, patients dragged their families into even deeper poverty by paying for ineffective treatments. So, what has changed? For a start, detection is quicker, because we help train health workers in areas reporting cases and target interventions in local hotspots of the disease. Perhaps the biggest leap forward in South Asia is the development of AmBisome, a single course, high-dose treatment that results in a clinical and parasitological cure in the majority of cases. By improving the cold chain for storage – in a climate that regularly exceeds 40 degrees - India’s health system is now better equipped to bring AmBisome to those poorer, remote communities where it is needed most.
Vulnerable communities
Of course, no disease is fair. But VL is especially unfair, as the sandfly thrives in areas of high poverty. Patients - traditionally the poorest of the poor - are unable to afford treatments. The economic burden of the VL illness on households can prove catastrophic. In over 12% of affected households in the six countries, the costs of seeking treatment accounted for over 40% of total annual household expenditure. The majority must use their savings or borrow money to pay for healthcare. KalaCORE is helping governments to reduce this burden by cutting the time between the onset of symptoms, correct diagnosis and proper treatment, and publicising the fact that effective treatment in the public sector is free, and even incentivised in some Indian states.
The WHO meeting in Geneva also provided a pause to re-focus on surveillance strategies that will achieve greater regulation of outbreaks in East Africa, which faces additional complex challenges. For a start, Ethiopia, Sudan and South Sudan are home to a different strain of the parasite, making AmBisome less suitable as a first line treatment. Moreover, the distinct ecology of the regional sandfly makes it harder to control with spraying, while livestock can also harbour the disease. Elimination here is all but impossible.
In the region, VL infections are instead treated by a combination therapy that lasts for 17 days. While this marks a welcome reduction from the old 30-day treatment, the risk of patient default remains that much higher. The treatment is very painful and also more toxic, adding another physical barrier for sections of society that already face hardships such as malnutrition and the HIV pandemic. These are the people least able to fight off a parasite.
East Africa also faces problems of population displacement, in particular caused by the civil war in South Sudan. Populations moving to new areas to escape conflict are rendered more vulnerable to disease as they lack the immunity acquired by local populations in endemic areas. KalaCORE’s mobile teams investigated seven suspected outbreaks in South Sudan in 2016. On one occasion in the war-torn Jonglei State, the team diagnosed 22 cases, and provided on-site training, test kits and drugs. These are areas with scarcely any infrastructure or recognisable health system, and with severe security constraints. So the mobile teams are demonstrating admirable commitment in reaching, responding to and containing these disease outbreaks in remote communities.
To date, KalaCORE has improved awareness of VL’s cause, prevention and treatment among 4.5 million people in South Asia and East Africa, training over 10,000 health workers in recognising and treating the disease. In total, over 11,000 VL patients were treated in 2016.
We’re delighted that the UK government has pledged to double its funding for NTDs to £360 million a year. This commitment will help sustain recent progress against VL. However, there’s no room for complacency. This journey is far from run. As with other horrible infections such as river blindness, guinea worm and sleeping sickness, VL has been neglected for too long. But now we know where it is. We know how to diagnose it. We know how to cure it. The truth is that VL offers great value for money in areas of the world that face the greatest poverty. It’s not a chronic disorder. If patients are diagnosed and treated in time, they can make a full recovery and usually within a matter of days.
This is a disease that brings real hope. It’s a matter of life or death.
Mott MacDonald is management agent for KalaCORE.
1. MSF receives no financial support from UKaid but contributes expertise to the partnership