Sand flies and wild animals sustain a natural infection from visceral leishmaniasis, making household pet exposure near forested and protected areas concerning for owners, according to a study published in PLOS Neglected Tropical Diseases.
“From the late 1980s onward, epidemics [of visceral leishmaniasis] have occurred in the urban environment, together with rapid expansion of transmission foci in hundreds of municipalities, including populous urban centers and several capitals,” Maria Rita Donalisio, PhD, from the department of public health at the State University of Campinas, and colleagues wrote. “The rural epidemiological pattern has been modified by increasing urbanization, while the geographic expansion of the disease has been observed in previously safe municipalities.”
The researchers note that little information is available on the subtleties of new outbreaks, as well as the environmental and epidemiological factors contributing to the disease or the hosts involved in the transmission cycles of various visceral leishmaniasis. However, increasing artificial and organic degradation of the environment is a concern for many areas throughout the world.
To examine Leishmania spp. infection in domestic dogs, wild mammals and sand flies in Campinas, Brazil, Donalisio and colleagues led a cross-sectional study of the visceral leishmaniasis focus, which included the use of molecular tools and recommended serological strategies.
The researchers observed a seroprevalence of 1.5% in canines in 2013. In 2015, seroprevalence in this species decreased to 1.2%. The researchers were also able to identify six insect species that carried confirmed or suspected vectors and were labeled as potential transmitters of Leishmania, including Nyssomyia whitmani (107 males, 47 females), Migonemyia migonei (81 males, 34 females), Pintomia fischeri (21 males, 12 females), Nyssomia neivai (12 males, 13 females), Pintomyia pessoai (three males, one female), and Lu. longipalpis (two males).
In an environmentally protected area, two Lutzomyia longpalpis, which were of the Leishmania infantum, vector were captured. One Expapillata firmatoi specimen and two Pintomyia monticola specimens demonstrated a natural L. infantum infection. In addition to sand flies, two white-eared opossums demonstrated a natural L. infantum and Leishmania subgenus Viannia.
Forest fragments in the environmentally protected area, which the CVL focus was located, had human residences nearby.
“The need to elaborate distinct control and prophylaxis strategies, according to the characteristics of each transmission area, including the rural and wild areas in the control programs, is now becoming evident,” Donalisio and colleagues wrote. “Studies that clarify the patterns of infection in different locations are useful for the success of such actions.” — by Katherine Bortz
Disclosure: The researchers provide no relevant financial disclosures.