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AUTOCHTHONOUS OUTBREAK OF LEISHMANIASIS IN URUGUAY CONSTITUTES THE SOUTHERNMOST FOCUS OF THE DISEASE

Autochthonous outbreak of leishmaniasis in Uruguay constitutes the southernmost focus of the disease

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Visceral Leishmaniasis (VL) is a zoonotic disease (a disease transmitted to humans by animals) caused by a Protozoan of the genus Leishmania, who’s vector is the sand fly (Lutzomia longipalpis). This disease affects both dogs and humans, dogs being the main reservoir of the parasite.

Although there are three types of leishmaniasis (visceral, cutaneous and mucocutaneous), the VL is the most serious form of the disease. In more than 95% of the cases it is deadly if untreated. Its symptoms are irregular episodes of fever, weight loss, hepatosplenomegaly (inflammation of the liver and spleen) and anemia.

Few years ago, Uruguay was geographically far away from the endemic area of VL, but its distribution started expanding towards the South of the continent, reaching border areas of our country. This situation aroused concern given that from that moment on the expansion of the disease within the Uruguayan territory was likely to occur, which eventually did happen. The first record of sand fly in Uruguay occurred in 2010 and in 2015 an outbreak of leishmaniasis in dogs was reported, being the southernmost record worldwide.

MORA case symptomatic index (left) and DUQUE second case detected symptomatic (right)

MORA caso indice sintomatico

 

 

 

 

 

In a joint effort, Universidad de la República, through the School of Medicine and the School of Veterinary, together with the Ministry of Public Health and the Institut Pasteur de Montevideo (IP Montevideo) responded swiftly to generate strategies for the prevention and treatment of the disease.

The Universidad de la República conducted surveys in the area where the first outbreak was detected, identifying other dog carriers of the disease and obtaining biological samples for further analysis. At the IP Montevideo, the Molecular Biology Unit performed the molecular typing of samples, which allowed to demonstrate that the species involved was Leishmania infantum. In turn, several isolates were obtained from parasites coming from infected dogs. These were characterised from a genetic point of view and resistance to drugs.

This situation changed Uruguay’s health status for Leishmaniasis, which led to the creation of a multidisciplinary team made up of experts from the Ministry of Public Health, the Universidad de la República and the IP Montevideo. The team developed the “Guide for diagnosis, treatment and control of Visceral Leishmaniasis in URUGUAY”, which was distributed in health centres around the country, aimed at all health care providers. After the distribution of the guide, some health centres requested support to perform training workshops, both in the capital and other cities.

Smear of ganglionar puncture of an infected dog. The figure shows a macrophage with Leishmania infantum amastigotes inside (arrow). Giemsa stain.

 

 

 

 

Leishmania infantum promastigotes in axenic culture obtained from infected dogs by ganglionar puncture.

 

Finally, we communicated the outbreak in the Emerging Infectious Disease Journal that was released on last march (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5382754/). Although, the appearance of canine cases puts us at risk of having human cases, they have not been reported in our country and we are certain that constant monitoring of the affected areas, fluid institutional interaction and the infrastructure to build a fast response will translate into prevention of human cases and, if necessary, rapid execute of control measures and diagnose that can derive in adequate medical treatment.