This article is more than 5 years old. Information may no longer be current.
Human encroachment in Uganda may increase risk for new disease patterns
Click Here to Manage Email Alerts
Researchers have identified a wide range of host exposure to mosquito vectors in an area affected by human encroachment in East Africa, suggesting an increased risk for the spread infectious diseases.
"The steady increase in contact between humans and wildlife is brought about by human encroachment, destruction of natural forests and environmental changes," the researchers wrote. "Mosquitoes get exposed to new hosts and pathogens; creating possibilities for new disease patterns."
The researchers, who presented their findings at the American Society of Tropical Medicine and Hygiene annual meeting in Washington, D.C., performed genetic sequencing on the blood meal of engorged mosquitoes collected in the Zika Forest in Uganda over a 12-month period.
The sequences were searched in Genbank database, which indicated the presence of mammalian (86%), avian (13%) and amphibian (1%) hosts. According to the researchers, the first record of human blood was identified in the Uranotaenia mashonaensis species, which are known to feed exclusively on reptiles, amphibians, birds or domestic mammals.
There were significant differences observed between host species (P.018), which may put humans and other species at risk of exposure to new pathogens.
According to study researcher Martha A. Kaddumukasa, PhD, of Makerere University in Uganda, the movement of culine and anopheline mosquitoes — particularly Aedes aegypti and Aedes africanus females — between sylvatic and urban environments increases the risk for infection in humans.
"Capacities of female mosquitoes to disperse from a sylvatic into a human-modified environment suggest that these species may play a role in the dissemination of forest-restricted pathogens, such as dengue, chikungunya and yellow fever viruses and malaria," Kaddumukasa told Infectious Disease News. "Many prevalent human diseases are linked to dissemination of forest-restricted pathogens and altered transmission of infectious diseases."
Kaddumukasa said constant mosquito vector surveillance and raising awareness of the dangers associated with vector-borne pathogens are important steps to minimize mosquito vector contact with humans and wildlife.
"However, clinicians should work with other scientists to brace themselves for any outbreaks of infections," she said. "With the outbreak of disease, clinicians should work with the surveillance teams to quickly arrest epidemic situations of infections."
For more information:
Kaddumukasa MA. Abstract #1109. Presented at: American Society of Tropical Medicine and Hygiene annual meeting; Nov. 13-17, 2013; Washington, D.C.
Disclosure: The researchers report no relevant financial disclosures.
Perspective
Back to Top
Bernard A. Okech, MS, PhD
This abstract by Kaddumukasa and colleagues, presented at the 62nd ASTMH meeting in Washington, D.C., highlights the dangers of environmental degradation, particularly when humans encroach into forestland. Previous studies have shown how human activities and settlements in forestland increases ecological niches for malaria mosquitoes, leading to increased malaria transmission risk in Africa (Afrane YA. Emerg Infect Dis. 2008;14:1533-1558) and the Amazon (Confalonieri UE. Acta Trop. 2013;doi:10.1016/j.actatropica.2013.09.013; Vittor AY. Am J Trop Med Hyg. 2006;74:3-11). Higher transmission risk for New World leishmaniasis also has been observed when humans encroach forests. Although the findings of Kaddumukasa and colleagues represent new information about the feeding host range of Uranotaenia species in Uganda, it is not surprising because it also has been observed elsewhere when humans encroach forests. The findings of the study are important in highlighting the unforeseen consequences of human encroachment into forests whereby host ranges of mosquito vectors are expanded, thus increasing the risk for transmission of novel diseases to man or vice versa.
Click Here to Manage Email Alerts