Emerging parasitic disease mimics the symptoms of visceral leishmaniasis in people - National Institutes of Health (.gov)

Media Advisory

Tuesday, October 1, 2019

What

A new study published this week online in Emerging Infectious Diseases suggests that transmission of a protozoan parasite from insects may also cause leishmaniasis-like symptoms in people. The parasite, however, does not respond to treatment with standard leishmaniasis drugs. The research was conducted by scientists at the Federal Universities of Sergipe and São Carlos, the University of São Paulo, and the Oswaldo Cruz Foundation, all in Brazil, along with investigators at the National Institute of Allergy and Infectious Diseases (NIAID), part of the U.S. National Institutes of Health.

Leishmaniasis is a parasitic disease found in parts of the tropics, subtropics, and southern Europe. It is classified as a neglected tropical disease and is often transmitted by the bite of some sand flies. The most common forms of leishmaniasis are cutaneous, which causes skin sores, and visceral, which affects several internal organs (usually spleen, liver, and bone marrow). According to the World Health Organization, each year between 50,000 and 90,000 people become sick with visceral leishmaniasis (kala-azar), a form of the disease that attacks the internal organs and is fatal in more than 95 percent of cases left untreated. During the last several decades, researchers have described rare cases of patients co-infected with both Leishmania and other groups of protozoan parasites that usually infect insects, including Crithidia. The current study of parasites isolated from a Brazilian patient confirms that Crithidia parasites also can infect people.

The 63-year-old patient initially sought treatment for the symptoms of visceral leishmaniasis, including weight loss, fever, anemia, and an enlarged liver and spleen. However, after eight months of standard leishmaniasis treatment, the patient's symptoms had not improved. The patient developed widespread skin lesions with poorly defined edges (unlike the small lesions with well-defined edges that sometimes appear after treatment for visceral leishmaniasis) and ultimately died.

To determine the cause of disease, researchers cultured parasites taken from the patient's bone marrow and skin lesions, sequenced their genomes, and discovered that the parasites were not closely related to known disease-causing Leishmania parasites. Instead, they were more closely related to Crithidia fasciculata, a parasite that usually colonizes mosquitoes. To confirm that these Crithidia parasites could infect mammals, the researchers exposed mice to the parasites isolated from the patient, both intravenously and by injection into the skin, and found that both types of parasite infected the liver. The parasites collected from the patient's skin also caused skin lesions in the mice.

The study raises concerns that the Brazilian patient might not be an isolated case. If Crithidia infections represent an emerging infectious disease in people, there will be an urgent need to develop novel effective treatments, the researchers write. They expressed concern that the disease may be mosquito-borne because Anopheles and Culex mosquitoes can host the Crithidia parasite. More research will be needed to find other human cases, confirm the parasite's range and host species, and discover potential treatments, the authors note.  

Article

Maruyama et al. Non-Leishmania Parasite in Fatal Visceral Leishmaniasis–like Disease, Brazil. Emerging Infectious Diseases DOI: 10.3201/eid2511.181548 (2019).

Who

José M. Ribeiro, M.D., Ph.D., Chief of the Vector Biology Section in NIAID's Laboratory of Malaria and Vector Research, is available for comment on this study.

NIAID conducts and supports research — at NIH, throughout the United States, and worldwide — to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses. News releases, fact sheets and other NIAID-related materials are available on the NIAID website.

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.

NIH…Turning Discovery Into Health®

###

Adblock test (Why?)

Comments

Post a Comment

Popular posts from this blog

Roseola rash: symptoms, pictures, and treatment - Medical News Today

Image
Roseola rash occurs due to infection from a type of herpes virus. It typically affects babies and toddlers and people may confuse it with measles. However, both conditions have different causes, presentations, and complications. Other names for this health issue are sixth disease, exanthema subitum, or just "roseola." Around 90% of roseola cases occur before 2 years of age. This article summarizes how to identify roseola and how to tell the difference between this illness and measles. It also examines whether treatment is necessary. Roseola usually affects toddlers and babies under 2 years old . They may also have or show: general discomfort irritability an unwillingness to eat diarrhea a cough swelling or redness around the eyes ear pain swollen glands Roseola has a distinctive progression : A high fever develops, possibly suddenly, and may last for 3–5 days. A distinctive rash appears, usually on the torso, as the fever ends. The rash may progress to the neck, face, and li...
Read more

CDC says skin-disfiguring parasite may be endemic in Texas, present in other states - NBC News

Image
A parasite capable of causing a disfiguring skin disease may be endemic in Texas and present in other southern states, according to the Centers for Disease Control and Prevention. From 2005 to 2019, the CDC identified 1,222 cases in the U.S. that were positive for Leishmania, a parasite transmitted through the bites of infected female sandflies. The parasite can cause a disease called leishmaniasis, which usually results in skin sores that develop within a few weeks or months after a bite. Leishmaniasis cases in the U.S. are typically found in people who traveled outside the country to tropical or subtropical climates — particularly those in the Middle East, central Asia, northern Africa and Latin America.  But the CDC said 86 of the Leishmania samples were from people with no recent history of travel outside the U.S. The researchers also detected a unique strain of Leishmania that appeared to be genetically distinct from travel-related cases, suggesting it w...
Read more