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American Trypanosomiasis - Chagas Disease1 Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office. ENY-726 Blood Feeding Insect Series: American Trypanosomiasis - Chagas Disease1 Kevin Kobylinski and Roxanne Rutledge Connelly2 What is Chagas Disease? • Enlarged lymph nodes, liver, or spleen American trypanasomiasis, also known as Acute infections are treatable using medications Chagas disease, is a potentially fatal, chronic disease prescribed by a physician. that currently affects twelve million people Symptoms of chronic cardiac infection in throughout Mexico, Central and South America. The humans include: disease is caused by a protozoan parasite, Trypanosoma cruzi. T. cruzi is transmitted to humans • Heart palpitations and animals by triatomine bugs, commonly referred to as "kissing bugs" (Fig. 1). Additionally, humans • Dizziness can contract the disease from blood transfusions with contaminated blood. • Chest pain Chagas disease can cause different symptoms • Fainting depending on the location of the parasite in muscle Chronic Chagas infection of the cardiac muscle tissue. Acute infections can be fatal, but most will eventually result in cardiac failure and death of humans survive acute infection. Acute symptoms the host. There are no cures for chronic Chagas include: infection. Heart transplants can delay death, but the • Romañas sign: an obvious swelling of the protozoans will still remain in other muscle tissue and eye and surrounding area can re-infect cardiac muscle. Other deleterious effects of Chagas disease include mega-colon, • Fever mega-esophagus and encephalitis in small children. • Skin rash 1. Part of a series of EDIS Fact Sheets on diseases transmitted by blood-feeding insects. This document is ENY-726, one of a series of the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date March 2006. Revised July 2010. Visit the EDIS Web Site at http://edis.ifas.ufl.edu. 2. Kevin Kobylinski is a former graduate student in the UF/IFAS Dept. of Entomology and Nematology. Roxanne Rutledge Connelly is associate professor in the UF/IFAS Dept. of Entomology, Florida Medical Entomology Laboratory, Vero Beach, FL, 32962. The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Millie Ferrer-Chancy, Interim Dean Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office. Blood Feeding Insect Series: American Trypanosomiasis - Chagas Disease 2 in the blood stream and can be transmitted to uninfected triatomine bugs that feed on the host. After two to six weeks, the acute phase ends and the chronic phase begins. During the chronic phase, the protozoans will replicate in the smooth muscle tissue and are rarely found circulating in the bloodstream. After a triatomine bug has fed on an infected host, the parasite will begin to multiply in the insect midgut and remain until it is expelled in the feces during the next blood meal. Figure 1. Top: Female Triatoma gerstaeckeri. Bottom: Wild and Domestic Animals as Reservoirs Male Triatoma sanguisuga. Credits: S. A. Kjos, Texas A & M University Reservoirs for the parasite that causes Chagas disease are armadillos, badgers, coyotes, opossums, Life Cycle of Triatomine Bugs raccoons, skunks, wood rats, and many rodent There are 105 known species of triatomine bugs species. Opossums are particularly important in in the Western hemisphere. Each species has unique South America because the parasite can complete its biological characteristics that affect their ability to life cycle in the anal glands of this marsupial. transmit the parasite. The average life expectancy Domesticated animals such as cattle, sheep, dogs from egg to adult can range from three months to two and cats are potential reservoirs as well. Animals can years, depending on the species. Triatomine bugs are easily become infected with T. cruzi when an infected hemimetabolous, which means the young look triatomine bug is ingested. Dogs and cats play an similar to the adults. The immature bug will molt five important role as reservoirs in many South American times before it becomes a reproductive adult. The transmission cycles. juveniles feed at least once during each molting stage, and the adults will feed multiple times. Triatomine Clinical symptoms of T. cruzi infection in dogs males and females both feed on blood. Feeding on are difficult or labored breathing. Dogs can contract humans occurs at night when the host is asleep. Chagas disease in either urban or rural settings. Chronic, cardiac infections of the parasite can be fatal Transmission Cycle of Chagas Disease to dogs. While little can be done for chronic Often times, Latin American triatomines will infections, acute infections can potentially be treated feed near the eyes and lips, earning them the common with medication by a veterinarian. name “kissing bugs”. Feeding near the eyes and lips greatly increases the risk of transmission of T. Is there a risk of contracting Chagas cruzi. Unlike many arthropod-borne diseases, T. cruzi Disease for Florida citizens? is not transmitted to humans directly by the bite of the Chagas Disease is one of the rare vector-borne infected insect. Triatomine bugs defecate while diseases which is succumbing to control efforts in the blood-feeding. If the insect is infected with the Americas. Improved housing and the application of parasite, it can enter the bloodstream when the host residual insecticides to control triatomine bugs are scratches the irritated bite wound. important for reducing the number of people infected The parasite then replicates within the with the parasite. bloodstream of the host - this is known as the acute In the southeastern United States, infected phase. It takes one to two weeks after introduction of triatomine bugs and reservoir hosts have been found the parasite for the acute phase to be manifested. from Texas to Florida and as far north as Oklahoma During the acute phase, the parasite is readily found and Maryland. However, there is minimal chance of transmission to humans. Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office. Blood Feeding Insect Series: American Trypanosomiasis - Chagas Disease 3 The high disease prevalence throughout Latin Control of Triatomine Bugs America is due primarily to human dwellings being suitable habitats for triatomines. Earthen floors, The probability of human or pet infection in the thatched roofs and mortared brick walls are all southeastern U.S. is very low. Unless there is inviting habitats for large populations of domesticated evidence of T. cruzi transmission and pathology, triatomines. These living conditions are not prevalent insect control is not necessary. If it becomes in the United States and thus human/vector contact necessary to implement control measures, the drastically decreases. following information can be useful. There are many species of triatomine vectors in Triatomines found in the southeastern United the southeastern United States, but only Triatoma States typically live in close association with sanguisuga and Triatoma gerstaeckeri are of major burrowing animals. Any burrowing animal, concern due to their high abundance. Triatoma especially wood rats, located within thirty meters of sanguisuga is found in Florida, while Triatoma human dwellings should be removed and its nest gerstaeckeri is not. Feeding habits of T. sanguisuga destroyed. This is very important if kissing bugs are and T. gerstaeckeri differ from their Latin American observed inside of human or domestic animal counterparts. T. sanguisuga and T. gerstaeckeri are dwellings and if there is evidence of transmission of very cautious and neither will walk completely onto a the parasite. If these animals are found on your host, reducing the chances of defecating on the host. property - armadillos, badgers, coyotes, oppossums, Both T. gerstaeckeri and T. sanguisuga generally do raccoons, skunks, wood rats or other rodent species, not defecate while feeding, reducing fecal contact along with triatomine vectors in the home - removal with the wound even further. of the animals should be considered. Infection from the blood supply? To reduce possible infection to dogs, homeowners may want to remove all burrowing The main threat of contracting Chagas Disease to animals from their property if possible. Dogs, by Florida residents is from blood transfusions with nature, are very curious and will seek out burrowing contaminated blood. More than one million native rodents, thereby coming into contact with vectors Latin Americans live in the United States and they are more frequently. estimated to have infection rates as high as 10%. A vast majority of people infected with the parasite will Lights attract triatomines at night. Any entrances not develop clinical symptoms for ten to twenty years. or openings to the home close to the lights should be This means
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