Leishmaniasis is caused by a parasite transmitted by the bite of an infected phlebotomine sand-fly. It presents in different ways in people. Cutaneous types may lead to skin sores that are self-healing in a few months though they can leave ugly sores. There is visceral Leishmaniasis which causes systemic disease. It presents with weight loss, anemia, and swelling in the liver and lymph nodes. Vaccines are not yet available for the infection, so the best way for travelers to prevent disease is protecting themselves from bites.
History of the Leishmaniasis Disease
The disease has a long history which goes back to the first century. During this time, pre-Incan pottery from Peru and Ecuador showed illustrations of facial deformities and lesion are part of the disease symptoms. South American text from the 15th and 16th century mentioned accounts from the Spanish conquistadors who described skin lesions on agricultural workers that were coming back from the Andes. In Africa and Asia, reports about the disease came later during the 18th century. What was later identified as visceral Leishmaniasis was called ‘black fever’, or ‘Kal-Azar’.
The condition attained its name, Leishmaniasis when William Leishman, a doctor with the British Army in India, discovered one of the first strains. In 1901, near Calcutta, he found ovoid bodies within the spleen of a soldier who had been experiencing anemia, muscular atrophy and fever. The illness was described as ‘dum-dum’ fever and published among his findings in 1903. Another doctor, Charles Donovan, also discovered similar symptoms in the other Kal-Azar patients then announced the discovery some weeks after Leishmaniasis.
Types of Leishmaniasis
The disease presents in three types which include visceral, cutaneous and mucocutaneous. The different species of the parasite are linked with each form. Cutaneous Leishmaniasis leads to skin ulcers, and treatment may not be needed depending on the severity of the case. Mucocutaneous Leishmaniasis registers from the cutaneous form of the parasite and is there several months after the skin ulcers begin to heal. The parasite spreads to the throat, mouth and nose, harming the mucous membranes in these areas. Even though mucocutaneous Leishmaniasis is usually seen as a subset of Cutaneous Leishmaniasis, it appears to be more serious. The third iteration is visceral Leishmaniasis or systemic Kal-Azar. That usually occurs between two and eight months of being bitten by the sand-fly. The result is damage to the internal organs like the spleen and the liver. It can also damage the immune system after organ failure has occurred.
Causes of Leishmaniasis
As mentioned, the leishmaniasis disease is spread by protozoan parasites of the Leishmania species living within sand flies. The parasites live and multiply within female sand flies particularly. The insect is the most active within humid settings, especially at night. Domestic animals such as pets and livestock may act as carriers for the parasite when they are bitten. They can transfer the parasite to people. Humans may also transfer the parasite to others through blood transfusions.
Risk factors of the disease
From a geographic point of view, the condition is most often located within the tropics and other warm, humid areas. Though, occurrences of the disease have been everywhere except Australia and Antarctica. Most of the cutaneous cases occur in Asia, South America, and the Middle East. Most of the visceral cases have come from Kenya, Somalia, South Sudan and India. Studies by the world health organization have determined that poverty is one of the determining factors for infection risk in less developed nations. Leishmaniasis usually occurs where malnutrition, famine and lack of financial resources are common.
People who have weak immune systems are also at increased risk of the disease. HIV infection may create a suitable weakened environment for the transmission of the disease, considering they affect similar cells within the immune system.
It is crucial to inform a physician of visits to areas where Leishmaniasis is prevalent. That way, they will know to test for the presence of the parasite. Diagnosis entails taking a small amount of skin for a biopsy by scraping one of the ulcers. The doctor will search for the genetic material of the parasite. Though, this method usually applies to the cutaneous variety. A lot of times, people do not remember being bitten by a sand-fly, and so it can make the condition hard to diagnose. The doctor may first do a physical evaluation to look for an enlarged spleen. They may eventually perform a bone marrow biopsy or take a blood sample for assessment.
Cutaneous versions of the disease usually heal without much attention. Though, treatment can help the healing process along and reduce the amount of scarring while decreasing the risks of further illness. Visceral Leishmaniasis always requires attention. Some of the medications used include amphotericin B, Paromomycin and Pentostam. The lesions caused by mucocutaneous iterations also need treatment. There are interventions like paromomycin and Liposomal amphotericin B.
Preventing infection is the most effective means of controlling the disease. In the places where it is prevalent, one can take steps to avoid being exposed to sandflies, especially when they are active. That means using insect repellent which has DEET from dusk to dawn and donning clothing over the arms and legs. People should also remain within well-screened places at night and use netting for beds. The clothing should also be treated with insecticides like pyrethrum as a deterrent for the sand flies.
For the most part, Leishmaniasis is often superficial, considering the cutaneous infections only cause skin ulcers. However, visceral types are often fatal because of the effects the disease has on the internal organs and weakening of the immune system. The complications experienced from the cutaneous type include bleeding, disfigurement of the limbs and face, as well as other infections from a weakened system. Individuals who are already immune-compromised from HIV and other ailments suffer a higher risk of getting the disease. Socio-economic factors are considered in sand fly regions which have famine and high rates of poverty.