Non-UK Infections

Overview

Leishmaniasis is a protozoan infection caused by >20 various species of the Leishmania parasites. The disease is transmitted via the bite of infected female phlebotomine sand flies. There are three main forms of the disease: cutaneous Leishmaniasis, visceral Leishmaniasis (kala-azar) and mucosal Leishmaniasis. Leishmaniasis cases occur in >90 countries in the tropics, subtropics and southern Europe. Cases have been reported in the UK usually after travel to a Mediterranean area. Overall, >12 million individuals in 88 countries have been reported as infected. The overall estimation is much higher due to the asymptomatic nature of some cases and missing data from rural areas. The disease usually occurs in rural areas but has been reported in the outskirts of some cities.

 

Cutaneous Leishmaniasis is the most common form where ulcers form leading to disfigurement, permanent scars, stigma and in some cases disability. The causative organism for this particular form is endemic to Afghanistan, Algeria, Brazil, Colombia, the Islamic Republic of Iran, Pakistan, Peru, Saudi Arabia and the Syrian Arab Republic.

 

Visceral Leishmaniasis is the most severe form and is fatal if left untreated. The causative organism in this case is endemic to Bangladesh, Brazil, Ethiopia, India, South Sudan and Sudan. WHO estimated 300,000 new cases of visceral Leishmaniasis per year, 20,000-30,000 deaths annually and a population of 310 million at risk. Untreated visceral Leishmaniasis has a mortality rate of 75-95% opposed to 10% when given treatment.

 

Mucosal Leishmaniasis destroys the mucosal membranes in the nose, mouth and throat. Around 90% of mucocutaneous Leishmaniasis cases occur in Bolivia, Brazil and Peru. 1 million new cases of cutaneous and mucocutaneous are estimated to occur annually.

 

Signs and symptoms

The three clinical syndromes present with varied signs and symptoms.

Visceral Leishmaniasis has an incubation period of 3-8 months. It can often be the presenting feature of HIV infection. Visceral Leishmaniasis disease infects the liver, spleen and bone marrow causing symptoms of:

• Night sweats

• Weakness

• Anorexia

• Fever

• Weight loss

• Hepatomegaly

• Splenomegaly (often enormous)

• Anaemia and pancytopenia

• Hypergammaglobulinaemia (high gamma globulin levels)

• Dark pigmentation of the skin which is usually dry, thin and scaly

 

Cutaneous Leishmaniasis has an incubation period of 2 weeks to

several months. It can present in various forms. The majority of cases

have limited cutaneous lesions which are self-limiting within 6-18 months.

The disease begins as small, dry erythrematous patches which develop

into painless plaques and large, deep ulcers with a granulating base

and overlying exudate. Lesions can occur singly or in groups and often

form on exposed body areas such as the face, arms and legs.

Swollen glands present near the sore and pain is present in the case of

secondary bacterial infections.

 

Mucocutaneous Leishmaniasis is usually acquired after initial infection

of cutaneous Leishmaniasis, usually after inadequate treatment.

Months to years after cutaneous infection, mucous membranes are involved to present with signs and symptoms of:

• Inflammation of the nose, oral cavity, pharynx, larynx and trachea

• Nasal stuffiness, discharge or epistaxis

• Destroyed nasal septum which can result in nasal collapse

• Respiratory difficulties

• Malnutrition due to destruction of oral cavity and larynx mucous membranes

• Aspiration pneumonia

 

Causes

Leishmaniasis is transmitted by the bite of infected female phlebotomine sand flies. Promastigotes are injected into the human bloodstream during the consumption of blood. Promastigotes are then phagocytized by macrophages other mononuclear phagocytic cells where they transform into the tissue stage of the parasite (amastigotes). Amastigotes multiply and proceed to infect other mononuclear phagocytic cells.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

At risk groups / risk factors

Individuals are more at risk of Leishmaniasis in areas where sand fly breeding and nesting is prevalent and where sand flies find humans more exposed and easily accessible.

• Poor socio-economic conditions

• Malnutrition - diets low/lacking in protein, iron, vitamin A and zinc increase the risk of infection progress to visceral Leishmaniasis

• Poor housing or including sleeping outside on the ground

• Poor domestic sanitation attracts flies

• Mass population movements which move non-immune individuals into endemic areas

• Deforestation – moving individuals into deforested areas inhabited by sand flies can rapidly increase cases

• Environmental changes such as urbanisation and initiating agriculture into forested areas – increase sand fly contact to non-immune people and livestock

• Climate change - Leishmaniasis is affected by changes in rainfall, temperature and humidity. Global warming and land degradation can affect sand fly populations and expand the geographical area in which the parasite is able to replicate

• Drought, famine, flood and other natural disasters cause population movements 

• HIV infection and immunocompromised individuals 

• Sharing of needles, sexual intercourse, transplacental infection and organ transplantation (rare) 

 

Diagnosis and microbiology testing 

 

 

 

 

 

 

 

 

 

 

 

 

 

Treatment  

Drug resistance, treatment failures and relapses are becoming increasingly common in treatment with pentavalent antimony compounds (sodium stiboglutamate or meglumine antimoniate). The recommended dose of pentavalent antimony compounds is 20mg/kg/day for 20-28 days depending on the clinical syndrome.  

Liposomal amphotericin B is licensed for the treatment of visceral Leishmaniasis. It has equal therapeutic effective to pentavalent antimony compounds but less toxic properties. Duration of treatment lasts 5-10 days and can even be given as a one-off stat dose in less severe cases. 

Fluconazole and Itraconzole have shown to be effective in the treatment of cutaneous Leishmaniasis.  

Miltefosine has been used with success for treatment of cutaneous and visceral Leishmaniasis in developing countries where first line medication was not available. 

Topical treatment using paromycin and methylbenzethonium has been successful in cutaneous Leishmaniasis. 

 

Vaccines / preventative measures 

There is currently no vaccine available. Preventative measures include controlling animal reservoirs, treating infected humans and controlling sand fly vectors through the use of insecticides, bed nets etc.