New tropical disease detected in Brazil defies treatment
- New disease damages liver, spleen and skin and is resistant to available treatments
- Caused by a parasite, disease combines symptoms of visceral and cutaneous leishmaniasis
- It is unknown where the parasite lives or how it is transmitted
The disease caused by the Cridia sergipensis parasite is suspected to have infected more than 150 people and caused two deaths in Sergipe state, in the northeast of the country.
Symptoms are similar to those of both the visceral and cutaneous forms of leishmaniasis – a neglected tropical disease spread by infected female sandflies – with the parasite attacking both the skin and internal organs.
However, the new disease does not respond to conventional treatments for leishmaniasis.
“This paper represents the first description of a new type of parasitic disease caused by trypanosome-like organisms. It expands the list of parasitic diseases in South America and raises awareness about the importance of identifying novel infectious illnesses,”
Alejandro Ulloa-Morales, Max-Planck-Institute for Molecular Physiology, Germany
The species was described in the journal Emerging Infectious Diseases by researchers from several Brazilian universities in cooperation with the US-based National Institute of Allergy and Infectious Diseases.
The first confirmed case was a 64-year old patient in Sergipe in 2011 who showed symptoms similar to visceral leishmaniasis but did not respond to treatment and died.
There are more than 20 known species of Leishmania, classified into three main forms: cutaneous, mucosal and visceral. Visceral is the most severe form of the disease and is fatal if left untreated.
Depending on the type of leishmaniasis contracted, symptoms appear in weeks to months after the sandfly bite and include weight loss, low blood count, enlargement of the liver and spleen, and fever.
Roque Pacheco de Almeida, head of the molecular biology laboratory at Aracaju University Hospital in Sergipe, has been treating patients affected by the new disease. He told SciDev.Net the first patient he saw also had skin lesions and irritations, typical of the cutaneous form of leishmaniasis.
“The [first] patient was refractory to treatment. The biopsy revealed the presence of parasitic macrophages [large white blood cells that ingest infectious microorganisms]. We thought at first that the parasite was resistant. After genome sequencing came the surprise: it was a new agent.”
João Santana da Silva, a specialist at the Center for Research in Inflammatory Diseases (CRID) of the University of São Paulo, and co-author of the article, said: “Today we have several patients with this parasite and we need to verify whether it is an isolated infection or a co-infection with leishmaniasis.”
Besides Sergipe, there are suspected cases in other parts of the northeastern region, yet to be confirmed, Silva added.
“This is the first warning. We still need to diagnose where this parasite is located, what the vectors are, how it is transmitted, and develop an effective medicine. This process might take several months,” he admitted.
For now, patients are treated with the same medication used for leishmaniasis: a drug called methylglucamine antimoniate. It is the first-choice treatment for all three types.
According to microbiologist Alejandro Ulloa-Morales at Germany’s Max-Planck-Institute for Molecular Physiology, there is an urgent need to classify this new pathogen at a species level.
“This paper represents the first description of a new type of parasitic disease caused by trypanosome-like organisms. It expands the list of parasitic diseases in South America and raises awareness about the importance of identifying novel infectious illnesses,” he told SciDev.Net.
According to the World Health Organization, leishmaniasis is linked to environmental changes such as deforestation, the building of dams, and uncontrolled urbanisation. As the destruction of the Amazon rainforest intensifies, new exotic diseases will likely shift from predominantly “sylvatic cycles” [involving wild animals] to human or urban cycles.
“This puts pressure on local epidemiological systems to identify and classify promptly any new infectious agent, along with the execution of direct control measures such as elimination of the sandfly,” added Ulloa-Morales. A lack of funding for neglected diseases could stymie such efforts, warns João Silva. “We lack national and international funding. Between US$3 to 5 million would be needed to further advance this study,” he estimated.
Neglected tropical diseases are a diverse group of infectious diseases common in low-income populations in Africa, Asia and the Americas. They affect more than one billion people and cost developing economies billions of dollars every year.
Populations living in poverty, without adequate sanitation and in close contact with infectious vectors, domestic animals and livestock, are worst affected. As such these diseases often fail to garner the interest of the pharmaceutical industry.
Ulloa-Morales criticised pharmaceutical companies for slowing down research and development on infectious diseases, adding: “This puts tremendous pressure on basic researchers working in this field to look for novel approaches and to generate original pilot data for grant applications.”
This article was originally produced by SciDev.Net’s Latin America and Caribbean desk.
The study published in Emerging Infectious Diseases is funded by FAPESP, a donor of SciDev.Net.