The bed põrnikas may survive only equally unsafe equally its sinister cousin, the triatomine, or "kissing" bug. Influenza A virus subtype H5N1 novel report from Penn Medicine researchers inward the Center for Clinical Epidemiology as well as Biostatistics demonstrated that bed bugs, similar the triatomines, tin transmit Trypanosoma cruzi, the parasite that causes Chagas disease, i of the most prevalent as well as deadly diseases inward the Americas.
The role of the bloodsucking triatomine bugs equally vectors of Chagas affliction -- which affects half-dozen to 8 i thou 1000 worldwide, by as well as large inward Latin America, as well as kills most 50,000 a yr -- has long been recognized. The insects infect people non through their seize amongst teeth but feces, which they deposit on their sleeping host, often around the face, after feeding. Bed bugs, on the other hand, are ordinarily considered disease-free nuisances whose victims are left amongst alone itchy welts from bites as well as sleepless nights.
In a report published online this calendar week inward the American Journal of Tropical Medicine as well as Hygiene, senior writer Michael Z. Levy, PhD, assistant professor inward the division of Biostatistics as well as Epidemiology at the University of Pennsylvania's Perelman School of Medicine, as well as researchers at the Universidad Peruana Cayetano Heredia inward Republic of Peru conducted a serial of laboratory experiments that demonstrated bi-directional transmission of T. cruzi betwixt mice as well as bed bugs.
In the commencement experiment run at the Zoonotic Disease Research Center inward Arequipa, Peru, the researchers exposed 10 mice infected amongst the parasite to xx uninfected bed bugs every 3 days for a month. Of most 2,000 bed bugs used inward the experiment, the bulk acquired T. cruzi after feeding on the mice. In a dissever experiment to essay transmission from põrnikas to mouse, they constitute that ix out of 12 (75 percent) uninfected mice acquired the parasite after each i lived for xxx days amongst xx infected bed bugs.
In a tertiary experiment, investigators succeeded inward infecting mice past times placing feces of infected bed bugs on the animal's pare that had either been inflamed past times bed põrnikas bites, or scraped amongst a needle. Four out of 10 mice (40 percent) acquired the parasite past times this manner; 1 out of 5 (20 percent) were infected when the pare was broken past times the insect's bites only. Influenza A virus subtype H5N1 in conclusion experiment performed at the Penn bed põrnikas lab inward Philadelphia demonstrated that bed bugs, similar triatomines, defecate when they feed.
"We've shown that the bed põrnikas tin acquire as well as transmit the parasite. Our side past times side mensuration is to decide whether they are, or volition become, an of import histrion inward the epidemiology of Chagas disease," Levy said. "There are some reasons to worry -- bed bugs convey to a greater extent than frequent contact amongst people than kissing bugs, as well as at that spot are to a greater extent than of them inward infested houses, giving them ample chance to transmit the parasite. But peradventure at that spot is something of import nosotros don't yet empathize most them that mitigates the threat."
T. cruzi is too peculiarly at abode inward the guts of bed bugs. "I've never seen thence many parasites inward an insect," said Renzo Salazar, a biologist at the Universidad Peruana Cayetano Heredia as well as co-author on the study. "I expected a scenario amongst rattling depression infection, but nosotros constitute many parasites -- they actually replicate good inward the gut of the bed bugs."
Wicked Cousins
Bed bugs as well as kissing bugs are distant cousins but part many striking similarities. Both insects enshroud inward household cracks as well as crevices waiting for nightfall as well as the chance to feed on sleeping hosts. They are from the same guild of insects (Hemiptera) as well as both alone feed on blood. (One principal divergence is their size: kissing bugs are 5 times equally large equally a bed bug). With thence much inward common, it seemed logical to the authors that the kissing bug's most infamous trait, the transmission of T. cruzi, is too shared past times the bed bug.
Other investigators convey shared this suspicion. In 1912, only 3 years after Carlos Chagas described the transmission of the affliction past times kissing bugs, French parasitologist Émile Brumpt recounted that he had infected almost 100 bed bugs exposed to an infectious mouse, as well as and then used them to infect ii good for you lot mice. Decades afterwards an Argentine grouping replicated his work. These experiments, largely ignored during the recent bed põrnikas resurgence, missed i telephone substitution point.
"Mice tin hunt as well as consume bed bugs," said Ricardo Castillo-Neyra, DVM, PhD, coauthor as well as postdoctoral swain at the Universidad Peruana Cayetano Heredia as well as Penn. "The older studies were almost for sure alone documenting oral transmission of the parasite. Our operate shows for the commencement fourth dimension that bed bugs tin transmit the parasite when their feces are inward contact amongst broken skin, the road past times which humans are ordinarily infected."
Emerging Problem
More people inward the U.S. of A. are infected with T. cruzi now than ever before. The Centers for Disease Control as well as Prevention estimates that the issue of Chagas affliction cases inward the U.S. of A. today could survive equally high equally 300,000.
"There convey ever been triatomine bugs as well as cases of Chagas affliction inward the U.S., but the kissing bugs nosotros convey hither don't come upwards into homes oftentimes similar the to a greater extent than unsafe species inward South as well as Central America do," Levy said. "I am much to a greater extent than concerned most the role of bed bugs. They are already hither -- inward our homes, inward our beds as well as inward high numbers. What nosotros constitute has thrown a wrench inward the way I holler upwards most transmission, as well as where Chagas affliction could emerge next."
Equally worrying is the invasion of bed bugs into areas where Chagas affliction is prevalent, peculiarly inward countries where traditional insect vectors of the parasite convey been nearly eliminated, Levy said. In these areas, bed bugs volition survive repeatedly exposed to T. cruzi, as well as could re-spark transmission where it had been extinguished.
"Bed bugs are harder to kill than triatomines due to their resistance to mutual insecticides." Levy said. "No i is prepared for large scale bed põrnikas control. If the parasite starts to spread through bed bugs, decades of progress on Chagas affliction command inward the Americas could survive erased, as well as nosotros would convey no agency at our disposal to repeat what had been accomplished."
Often referred to equally a soundless killer, Chagas affliction is difficult to diagnose inward its early on stages because the symptoms are mild or absent. The parasites are hidden mainly inward the view as well as digestive musculus as well as over fourth dimension tin displace cardiac disorders as well as sometimes digestive or neurological problems. In afterwards years, the infection tin Pb to abrupt expiry or view failure caused past times progressive devastation of the view muscle. Although at that spot are some drugs to process Chagas disease, they acquire less effective the longer a somebody is infected.
The long asymptomatic menses of Chagas affliction complicates surveillance for novel outbreaks of transmission. In Arequipa, Peru, thousands became infected amongst the parasite earlier a representative appeared inward the hospital. The same could occur inward cities inward the U.S.A. if the parasite were to emerge inward the bed põrnikas populations, the authors say.
"Carlos Chagas discovered T. cruzi in triatomine insects earlier he saw a unmarried representative of the disease," Levy said. "We take away to acquire from his intuition -- depository fiscal establishment tally the bugs for the parasite."