We Cure People with Kala Azar,
one of the deadliest parasitic diseases in the world.
The Disease
Kala azar is a disease caused by a parasite that lives inside our white blood cells. The parasite is spread from person to person by the bite of an infected sandfly. The disease causes high fevers, malnutrition and overwhelming fatigue
Leishmania amastigotes living in a mammal. The big purple blob is a white blood cell. These amastigotes live inside the white blood cells as they cause disease.
the parasite
The parasite that causes kala azar in the "old world" is call Leishmania donovoni. They are very small, smaller than a red cell. This picture is a beautiful stain and with lots of the amastigotes present, but usually they are sparce and can be very hard to see!
We can find these by taking a sample from the spleen or lymph nodes but it takes a long time to evaluate so using blood tests for antibodies is the most common way to diagnose kala azar in low resource settings.
transmission
Kala azar is transmitted by a sandfly, an insect smaller than a mosquito. Phlebotomus orientalis is the sandfly that in South Sudan, Sudan, and Norther Ethiopia, transmits deadly kala azar. The female sandfly needs some protein to make eggs so she feeds on mammals like humans. That blood meal can give the parasite to the sandfly, or if the sandfly is already infected, can then infect the person. In fact, during an epidemic it is humans that are the main reservoir.
The sandflies come out to feed at sundown, but are so small they can fly right through normal mosquito nets.
Protection for infection is needed. Small mesh, or insecticide treated nets, or cloth nets are good protection. But who uses a net when you are cooking dinner - and remember the child you are breast feeding lying nearby. And in the season of the sandfly, March through May, it is so hot at night that it is not pleasant to sleep under a net if you do have one
Our season for sandflies is usually March through May or June when it is getting very hot out. The outbreaks of disease follow from August through January.
Picture curtesy of Walter Reed Hospital
Kala Azar - AN Epidemic in South Sudan
To the left is a chart showing the number of patients admitted to our hospital for kala azar treatment. In 2011 we treated over half the total kala azar patients in all of South Sudan during this epidemic year. And now in 2016 the numbers show that this epidemic is returning.
acacia forest
The sandflies of South Sudan, Sudan and Ethiopia live in the acacia balanites woodlands. They are not found with the cattle camps, and they are not peridomestic. People build their compounds up against the acacia woodlands, a good source of fire wood, but close enough to be exposed simply where they are living. Children walk to and from cattle camp through the cool of the woodlands, and sleep there completely unprotected.