Communicable diseases
Liam J. Donaldson, Paul D. Rutter in Donaldsons' Essential Public Health, 2017
Chagas disease is caused by a protozoan parasite, Trypanosoma cruzi. It largely occurs in Latin America, where around 7 million people are affected. It is starting to appear in some other countries. Its main route of infection is via the faeces of triatomine bugs, but it can result from blood transfusion or transplantation of organs. In the early stages of infection, symptoms are mild and nonspecific, although in a proportion of people there is a characteristic unilateral purple swelling of the eyelid. If the infection is not treated, it progresses so that parasites enter the heart, bowel or nervous system. It can then become life threatening. In the early stage of infection, antimicrobial drugs are highly effective but therapeutic benefit wanes the longer the person has the disease. Insecticide spraying in and around homes (the vector bug lives in the cracks and crevices within houses) can be very effective in destroying this vector.
Chagas’ Disease
F. Y. Liew in Vaccination Strategies of Tropical Diseases, 2017
Trypanosoma cruzi, the etiologic agent of Chagas’ disease, can become established in humans as well as in many other mammalian species and produce pathological conditions leading to death after either a relatively short acute phase or, more frequently, a protracted chronic period. Chagas’ disease represents a health problem of major proportions in South and Central America where, according to data compiled by the Pan American Health Organization, approximately 65 million people live in the endemic areas, 10 to 20 million are infected, and 10% of the latter present overt symptoms of the disease.1 The parasite and its vectors are widespread not only in the classical endemic areas but also in North America, where cases have been occasionally reported and the presence of T. cruzi in wildlife and reduviid insects has been repeatedly documented.2–9 Because infection in the endemic areas frequently occurs during childhood or youth, many patients are relatively young at the onset of the pathological conditions associated with Chagas’ disease (the reader is referred to the excellent recent reviews by Andrade and Andrade10 and Molina11 for an in-depth update on the pathology of Chagas’ disease). Because of this circumstance, many affected individuals encounter difficulties in performing strenuous physical efforts, the most common means of earning a living and supporting a family in the rural endemic areas. Thus, the health problem is compounded to become one of major socioeconomic proportions as well.
Bugs (The True Bugs)
Gail Miriam Moraru, Jerome Goddard in The Goddard Guide to Arthropods of Medical Importance, Seventh Edition, 2019
Chagas’ Disease. Kissing bugs may transmit Trypanosoma cruzi (Figure 13.10), the agent of Chagas’ disease, or American trypanosomiasis, one of the most important arthropod-borne diseases in tropical America. Chagas’ disease is a zoonosis (originally a parasite of wild animals) mostly occurring in Mexico and Central and South America (Figure 13.11), but at least 25 indigenous (locally acquired) cases have been reported in the southern U.S. as far north as Oklahoma.61–63 At present, the disease affects about 8 million people in Latin America,64 and at least 300,000 U.S. residents who have emigrated from Latin American countries.65,66 Chagas’ disease has both acute and chronic forms, but it is perhaps best known for the myocardial damage it causes with cardiac dilation, arrhythmias, and major conduction abnormalities, as well as digestive tract involvement such as megaesophagus and megacolon. The digestive form of Chagas’ disease is seen almost exclusively south of the Amazon basin and is rare in Central America and Mexico.67
Advances in preclinical approaches to Chagas disease drug discovery
Published in Expert Opinion on Drug Discovery, 2019
Fernando Villalta, Girish Rachakonda
Trypanosoma cruzi is the protozoan parasite that causes Chagas disease, also known as American trypanosomiasis. T. cruzi parasites are predominantly transmitted to humans as metacyclic trypomastigote forms (non-dividing) in the feces of infected hematophagous triatomine bugs at the bite site. Entry is either through the wound or transfer to neighboring mucosa. T. cruzi transmission can also occur congenitally, via organ transplantation, blood transfusion, or orally by ingestion of parasite-contaminated food and drink [1]. Infective trypomastigotes invade cells and differentiate into intracellular amastigotes, which multiply by binary fission to differentiate into trypomastigotes to further be released into the circulation as bloodstream trypomastigotes to infect cells again or to be ingested by another vector. The ingested blood trypomastigotes transform into epimastigotes in the vector’s midgut to multiply and then differentiate into infective metacyclic trypomastigotes. The infective trypomastigotes and intracellular replicative amastigotes are the clinically relevant life-cycle stages of the parasite that are targets for drug intervention.
Promiscuity in drug discovery on the verge of the structural revolution: recent advances and future chances
Published in Expert Opinion on Drug Discovery, 2023
Sarah Naomi Bolz, Michael Schroeder
Chagas disease is a potentially life-threatening infection caused by the protozoan parasite Trypanosoma cruzi that affects about 6–7 million people globally. It is recognized as a neglected tropical disease that primarily affects poor and marginalized populations in Latin America, leading to serious health consequences and socioeconomic burdens [96,97]. There are currently limited treatment options for Chagas disease, which have severe side effects and are only partially effective [98]. To identify novel medications, Adasme et al. performed a structure-based drug repositioning screening using interaction fingerprints [99]. They extracted the non-covalent protein–ligand interaction patterns from the available complex structures of 16 Chagas targets and screened the PDB to identify complexes with a similar binding mode. The screening yielded 38 top-hit compounds that showed high chemical diversity. Three of these repositioning candidates – ciprofloxacin, naproxen, and folic acid – displayed activity against the parasite when tested in vivo [99].
Overcoming challenges in the diagnosis and treatment of parasitic infectious diseases in migrants
Published in Expert Review of Anti-infective Therapy, 2020
Francesca F. Norman, Belen Comeche, Sandra Chamorro, Rogelio López-Vélez
Trypanosoma cruzi infection, Chagas disease, is considered a neglected tropical disease both in endemic and non-endemic areas. According to the Pan American Health Organization (PAHO), an estimated 65 million people are at risk of acquiring the disease, there are an estimated 6–8 million infected persons and 28,000 new acute cases are registered annually in endemic countries of the American continent [42]. Vector-borne, vertical, transfusion-transmitted and orally acquired T. cruzi infections are the main modes of transmission in endemic areas, but in non-endemic areas, infection may also be acquired (due to congenital transmission and rarely through blood transfusions/transplantation from infected donors) [43]. Currently, the congenital transmission route is the second most frequent globally and the main route for transmission in non-endemic countries. Following infection, an initial acute, often asymptomatic, phase occurs and the infection progresses to the chronic phase in the absence of specific anti-parasitic treatment. Many patients remain asymptomatic in the chronic phase but, after a period of decades, around 20-40% of the patients develop visceral involvement, mainly cardiomyopathy, arrhythmias, and/or enlarged viscera and occasionally neurological manifestations [43]. Although less frequent, reactivation of the disease may also occur, usually affecting immunosuppressed patients, presenting with severe and atypical manifestations involving the cardiovascular and central nervous system, with/without cutaneous involvement.
Related Knowledge Centers
- Brucellosis
- Chagas Disease
- Parasitism
- Surra
- Triatoma Infestans
- Trypanosoma
- Triatominae
- Disease Vector
- Feces
- Trypanosomatida