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Rokhsar JL, Raynor B, Sheen J, Goldstein ND, Levy MZ, Castillo-Neyra R. Modeling the impact of xenointoxication in dogs to halt Trypanosoma cruzi transmission. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.01.24.23284917. [PMID: 36747723 PMCID: PMC9901065 DOI: 10.1101/2023.01.24.23284917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Background Chagas disease, a vector-borne parasitic disease caused by Trypanosoma cruzi , affects millions in the Americas. Dogs are important reservoirs of the parasite. Under laboratory conditions, canine treatment with the systemic insecticide fluralaner demonstrated efficacy in killing Triatoma infestans and T. brasiliensis, T. cruzi vectors, when they feed on dogs. This form of pest control is called xenointoxication. However, T. cruzi can also be transmitted orally when mammals ingest infected bugs, so there is potential for dogs to become infected upon consuming infected bugs killed by the treatment. Xenointoxication thereby has two contrasting effects on dogs: decreasing the number of insects feeding on the dogs but increasing opportunities for exposure to T. cruzi via oral transmission to dogs ingesting infected insects. Objective Examine the potential for increased infection rates of T. cruzi in dogs following xenointoxication. Design/Methods We built a deterministic mathematical model, based on the Ross-MacDonald malaria model, to investigate the net effect of fluralaner treatment on the prevalence of T. cruzi infection in dogs in different epidemiologic scenarios. We drew upon published data on the change in percentage of bugs killed that fed on treated dogs over days post treatment. Parameters were adjusted to mimic three scenarios of T. cruzi transmission: high and low disease prevalence and domestic vectors, and low disease prevalence and sylvatic vectors. Results In regions with high endemic disease prevalence in dogs and domestic vectors, prevalence of infected dogs initially increases but subsequently declines before eventually rising back to the initial equilibrium following one fluralaner treatment. In regions of low prevalence and domestic or sylvatic vectors, however, treatment seems to be detrimental. In these regions our models suggest a potential for a rise in dog prevalence, due to oral transmission from dead infected bugs. Conclusion Xenointoxication could be a beneficial and novel One Health intervention in regions with high prevalence of T. cruzi and domestic vectors. In regions with low prevalence and domestic or sylvatic vectors, there is potential harm. Field trials should be carefully designed to closely follow treated dogs and include early stopping rules if incidence among treated dogs exceeds that of controls. Author summary Chagas disease, caused by the parasite Trypanosoma cruzi , is transmitted via triatomine insect vectors. In Latin America, dogs are a common feeding source for triatomine vectors and subsequently an important reservoir of T. cruzi . One proposed intervention to reduce T. cruzi transmission is xenointoxication: treating dogs with oral insecticide to kill triatomine vectors in order to decrease overall T. cruzi transmission. Fluralaner, commonly administered to prevent ectoparasites such as fleas and ticks, is effective under laboratory conditions against the triatomine vectors. One concern with fluralaner treatment is that rapid death of the insect vectors may make the insects more available to oral ingestion by dogs; a more effective transmission pathway than stercorarian, the usual route for T. cruzi transmission. Using a mathematical model, we explored 3 different epidemiologic scenarios: high prevalence endemic disease within a domestic T. cruzi cycle, low prevalence endemic disease within a domestic T. cruzi cycle, and low prevalence endemic disease within a semi-sylvatic T. cruzi cycle. We found a range of beneficial to detrimental effects of fluralaner xenointoxication depending on the epidemiologic scenario. Our results suggest that careful field trials should be designed and carried out before wide scale implementation of fluralaner xenointoxication to reduce T. cruzi transmission.
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Affiliation(s)
- Jennifer L. Rokhsar
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK,Department of Epidemiology and Biostatistics, Dornsife School of Public Health, Drexel University, Philadelphia, PA, USA,ORISE Fellow, Emerging Leaders in Data Science and Technologies Program Fellowship, National Institute of Allergy and Infectious Diseases (NIAID), NIH, USA
| | - Brinkley Raynor
- Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Justin Sheen
- Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA,Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Neal D. Goldstein
- Department of Epidemiology and Biostatistics, Dornsife School of Public Health, Drexel University, Philadelphia, PA, USA
| | - Michael Z. Levy
- Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA,One Health Unit, School of Public Health and Administration, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Ricardo Castillo-Neyra
- Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA,One Health Unit, School of Public Health and Administration, Universidad Peruana Cayetano Heredia, Lima, Peru,Corresponding author:
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Gabrielli S, Macchioni F, Spinicci M, Strohmeyer M, Roselli M, Nicoletti A, Cicero CE, Poma V, Rojo D, Lara Y, Gómez EBC, Rojas P, Gamboa H, Villagran AL, Cosmi F, Monasterio J, Cancrini G, Bartoloni A. Long-Standing International Cooperation in Parasitology Research: A Summary of 35 Years of Activities in the Bolivian Chaco. Trop Med Infect Dis 2022; 7:tropicalmed7100275. [PMID: 36288016 PMCID: PMC9611245 DOI: 10.3390/tropicalmed7100275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 09/21/2022] [Accepted: 09/24/2022] [Indexed: 11/16/2022] Open
Abstract
The Bolivian Chaco is a semiarid region with a low population density, situated in the southeast part of the Plurinational State of Bolivia. Here, despite the improvements of the last 15 years, poverty remains high in rural areas, where social vulnerability is widespread. The Guaraní ethnic group often lives in isolated communities with a low standard of hygiene and sanitation. This epidemiological scenario favors the spread of transmissible diseases, including several parasitic infections belonging to the neglected tropical diseases (NTDs) group. In this area, a long-standing research activity, built upon the synergism between local and foreign institutions, has been established since the late 1980s and helps to fill in the knowledge gap about the epidemiology dynamics of soil-transmitted helminths, vector-borne parasites, and other parasitic diseases. A 35-year history of cooperation programs in parasitology research has contributed to informing local health authorities of the NTD burden in the Bolivian Chaco and, ultimately, supports local healthcare providers in the management of parasitic diseases.
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Affiliation(s)
- Simona Gabrielli
- Dipartimento di Sanità Pubblica e Malattie Infettive, Sapienza Università di Roma, 00185 Rome, Italy
| | - Fabio Macchioni
- Dipartimento di Scienze Veterinarie, Università di Pisa, 56124 Pisa, Italy
| | - Michele Spinicci
- Dipartimento Medicina Sperimentale e Clinica, Università degli Studi di Firenze, 50121 Florence, Italy
| | - Marianne Strohmeyer
- Dipartimento Medicina Sperimentale e Clinica, Università degli Studi di Firenze, 50121 Florence, Italy
| | - Mimmo Roselli
- Dipartimento Medicina Sperimentale e Clinica, Università degli Studi di Firenze, 50121 Florence, Italy
| | - Alessandra Nicoletti
- Dipartimento di Scienze Mediche, Chirurgiche e Tecnologie Avanzate G.F. Ingrassia, Sez. di Neuroscienze, Università di Catania, 95125 Catania, Italy
| | - Calogero Edoardo Cicero
- Dipartimento di Scienze Mediche, Chirurgiche e Tecnologie Avanzate G.F. Ingrassia, Sez. di Neuroscienze, Università di Catania, 95125 Catania, Italy
| | - Veronica Poma
- Escuela de Salud del Chaco Tekove Katu, Gutierrez, Bolivia
| | - David Rojo
- Escuela de Salud del Chaco Tekove Katu, Gutierrez, Bolivia
| | - Yunni Lara
- Hospital San Antonio de los Sauces, Monteagudo, Bolivia
| | | | | | - Herlan Gamboa
- Facultad Integral del Chaco, Universidad Autónoma Gabriel René Moreno, Camiri, Bolivia
| | | | | | - Joaquín Monasterio
- Servicio Departamental de Salud (SEDES) de Santa Cruz, Santa Cruz, Bolivia
| | - Gabriella Cancrini
- Dipartimento di Sanità Pubblica e Malattie Infettive, Sapienza Università di Roma, 00185 Rome, Italy
| | - Alessandro Bartoloni
- Dipartimento Medicina Sperimentale e Clinica, Università degli Studi di Firenze, 50121 Florence, Italy
- Correspondence:
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Freitas NEM, Habib FL, Santos EF, Silva ÂAO, Fontes ND, Leony LM, Sampaio DD, de Almeida MC, Dantas-Torres F, Santos FLN. Technological advances in the serological diagnosis of Chagas disease in dogs and cats: a systematic review. Parasit Vectors 2022; 15:343. [PMID: 36167575 PMCID: PMC9516836 DOI: 10.1186/s13071-022-05476-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 09/10/2022] [Indexed: 11/12/2022] Open
Abstract
Background Chagas disease (CD) is caused by Trypanosoma cruzi, which is transmitted mainly through the feces/urine of infected triatomine bugs. The acute phase lasts 2–3 months and is characterized by high parasitemia and nonspecific symptoms, whereas the lifelong chronic phase features symptoms affecting the heart and/or digestive tract occurring in 30–40% of infected individuals. As in humans, cardiac abnormalities are observed in T. cruzi-infected dogs and cats. We reviewed the technological advances in the serological diagnosis of CD in dogs and cats. Methods A review of the published literature during the last 54 years (1968–2022) on the epidemiology, clinical features, diagnosis, treatment and prevention of CD in dogs and cats was conducted. Results Using predefined eligibility criteria for a search of the published literature, we retrieved and screened 436 publications. Of these, 84 original studies were considered for inclusion in this review. Dogs and cats are considered as sentinels, potentially indicating an active T. cruzi transmission and thus the risk for human infection. Although dogs and cats are reputed to be important for maintaining the T. cruzi domestic transmission cycle, there are no commercial tests to detect past or active infections in these animals. Most published research on CD in dogs and cats have used in-house serological tests prepared with native and/or full-length recombinant antigens, resulting in variable diagnostic performance. In recent years, chimeric antigens have been used to improve the diagnosis of chronic CD in humans with encouraging results. Some of them have high performance values (> 95%) and extremely low cross-reactivity rates for Leishmania spp., especially the antigens IBMP-8.1 to IBMP-8.4. The diagnostic performance of IBMP antigens was also investigated in dogs, showing high diagnostic performance with negligible cross-reactivity with anti-Leishmania infantum antibodies. Conclusions The development of a commercial immunodiagnostic tool to identify past or active T. cruzi infections in dogs and cats is urgently needed. The use of chimeric recombinant T. cruzi antigens may help to fill this gap and is discussed in this review. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05476-4.
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Affiliation(s)
- Natália Erdens Maron Freitas
- Advanced Health Public Laboratory, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Waldemar Falcão Street, 121, Candeal, Bahia, Salvador, 40296-710, Brazil
| | - Fernanda Lopes Habib
- Advanced Health Public Laboratory, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Waldemar Falcão Street, 121, Candeal, Bahia, Salvador, 40296-710, Brazil
| | - Emily Ferreira Santos
- Advanced Health Public Laboratory, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Waldemar Falcão Street, 121, Candeal, Bahia, Salvador, 40296-710, Brazil
| | - Ângelo Antônio Oliveira Silva
- Advanced Health Public Laboratory, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Waldemar Falcão Street, 121, Candeal, Bahia, Salvador, 40296-710, Brazil
| | - Natália Dantas Fontes
- Advanced Health Public Laboratory, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Waldemar Falcão Street, 121, Candeal, Bahia, Salvador, 40296-710, Brazil
| | - Leonardo Maia Leony
- Advanced Health Public Laboratory, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Waldemar Falcão Street, 121, Candeal, Bahia, Salvador, 40296-710, Brazil
| | - Daniel Dias Sampaio
- Brazil's Family Health Strategy, Municipal Health Department, Tremedal City Hall, Bahia, Tremedal, Brazil
| | - Marcio Cerqueira de Almeida
- Pathology and Molecular Biology Laboratory, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Salvador, Bahia, Brazil
| | - Filipe Dantas-Torres
- Laboratory of Immunoparasitology, Aggeu Magalhães Institute, Oswaldo Cruz Foundation, Recife, Pernambuco, Brazil
| | - Fred Luciano Neves Santos
- Advanced Health Public Laboratory, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Waldemar Falcão Street, 121, Candeal, Bahia, Salvador, 40296-710, Brazil. .,Integrated Translational Program in Chagas Disease From Fiocruz (Fio-Chagas), Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.
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Investigation on Prevalence of Canine Trypanosomiasis in the Conservation Areas of Bwindi-Mgahinga and Queen Elizabeth in Western Uganda. J Parasitol Res 2022; 2022:2606871. [PMID: 36124129 PMCID: PMC9482531 DOI: 10.1155/2022/2606871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Accepted: 08/18/2022] [Indexed: 11/18/2022] Open
Abstract
Nowadays, despite the instauration of several control strategies, animal trypanosomiasis continues to be reported all over Uganda. Few canine African trypanosomiasis (CAT) studies have been carried out, yet dogs are known Trypanosoma reservoirs that share identical home ranges with livestock and serve as parasite link between livestock and humans. This study evaluates the prevalence of CAT in dogs in the Bwindi-Mgahinga and Queen Elizabeth conservation areas. This information will be useful to evaluate the possible role of dogs in the transmission cycle of Trypanosoma species in livestock and wild animals. Trypanosome tests using microhematocrit centrifugation/dark ground microscopy technique (MHCT) followed by conventional polymerase chain reaction (cPCR) were performed in blood samples collected from identified indigenous dogs (
). Four (3.23%) out of 124 dogs were positive for CAT. One dog was positive with Trypanosoma congolense and three with T. vivax. There was no significant statistical difference in CAT prevalence rate in relation to dog’s age, sex, and site (
). This study reports what we believe is the first time detection of T. congolense and T. vivax in the indigenous dogs found in the Bwindi-Mgahinga and Queen Elizabeth conservation areas in western Uganda. The noticed T. congolense and T. vivax could be responsible for both canine and animal trypanosomiasis and represent a serious threat to the livestock industry. Therefore, there is a need for continuous trypanosomiasis surveillance and integrated management in contiguity to wildlife reserves.
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Spinicci M, Macchioni F, Gamboa H, Poma V, Villagrán AL, Strohmeyer M, Roselli M, Vargas R, Bartoloni A, Gabrielli S. Persistence of Trypanosoma cruzi vector-borne transmission among school-age children in the Bolivian Chaco documented by 24-month longitudinal serosurveillance. Trans R Soc Trop Med Hyg 2022; 117:58-60. [PMID: 35779279 PMCID: PMC9808515 DOI: 10.1093/trstmh/trac065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 05/25/2022] [Accepted: 06/16/2022] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Chagas disease represents a major public health concern in several Latin American countries, including Bolivia. METHODS We present a longitudinal serosurvey for Trypanosoma cruzi antibodies among a cohort of 120 school-age children from rural communities in the Bolivian Chaco at three time points between 2017 and 2019. Serum samples extracted from dry blood spots collected on filter paper were tested for T. cruzi antibodies by enzyme-linked immunosorbent assay and rapid diagnostic test. RESULTS T. cruzi antibodies were detected in 7/120 (5.8%), 8/120 (6.7%) and 11/120 (9.2%) samples in 2017, 2018 and 2019, respectively. An average incidence of 1.76 per 100 person-years was observed. CONCLUSIONS Our findings support the persistence of vector-borne T. cruzi transmission in this area, highlighting the need for strengthening multidisciplinary efforts against Chagas disease.
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Affiliation(s)
- Michele Spinicci
- Dipartimento di Medicina Sperimentale e Clinica, Università degli Studi di Firenze, Firenze, Italy,SOD Malattie Infettive e Tropicali, Azienda Ospedaliero Universitaria Careggi, Firenze, Italy
| | - Fabio Macchioni
- Dipartimento di Scienze Veterinarie, Università di Pisa, Pisa, Italy
| | - Herlan Gamboa
- Facultad Integral del Chaco, Universidad Autónoma Gabriel René Moreno, Camiri, Bolivia
| | - Veronica Poma
- Escuela de Salud del Chaco Tekove Katu, Gutierrez, Bolivia
| | | | - Marianne Strohmeyer
- Dipartimento di Medicina Sperimentale e Clinica, Università degli Studi di Firenze, Firenze, Italy
| | - Mimmo Roselli
- Dipartimento di Medicina Sperimentale e Clinica, Università degli Studi di Firenze, Firenze, Italy
| | - Roberto Vargas
- Servicio Departamental de Salud de Santa Cruz, Santa Cruz, Bolivia
| | | | - Simona Gabrielli
- Dipartimento di Sanità Pubblica e Malattie infettive, Università di Roma Sapienza, Roma, Italy
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Queiroga TBD, Gomez LCP, de Sena ER, Dos Santos WV, Ferreira HRP, de Araújo-Neto VT, Barbosa-Silva AN, Brito CRDN, Lima RKDR, Fagundes-Neto JC, Galvão LMDC, de Medeiros HR, da Câmara ACJ, Nascimento MSL, Gama RA, Guedes PMM. Insecticidal efficacy of fluralaner (Bravecto ®) against Triatoma brasiliensis, a major vector of Trypanosoma cruzi in Brazil. Parasit Vectors 2021; 14:456. [PMID: 34488865 PMCID: PMC8422713 DOI: 10.1186/s13071-021-04978-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 08/24/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Triatomines are responsible for the vector transmission of the protozoan parasite Trypanosoma cruzi, which causes Chagas disease. Triatoma brasiliensis is the main vector of the parasite in Brazil, and dogs are an important reservoir of the parasite. The aim of this study was to evaluate the insecticidal effect of fluralaner (Bravecto®) on T. brasiliensis after a blood meal in treated dogs. METHODS Healthy mongrel dogs (n = 8) were recruited from the Zoonoses Control Center (ZCC) in the city of Natal, Rio Grande do Norte, Brazil, and randomized into two groups, a fluralaner (Bravecto®)-treated group (n = 4) and a control group (n = 4). Colony-reared third-, fourth- and fifth-instar nymphs of T. brasiliensis nymphs (n = 10) were allowed to feed on dogs from both groups for 30-40 min, once monthly, for up to 12 months. Bug mortality was observed up to 5 days after each blood meal. RESULTS Mortality in triatomines which had a blood meal on fluralaner (Bravecto®)-treated dogs was 100% for up to 7 months after treatment, with mortality decreasing to 66.4% after 8 months, 57% after 9 months, 35% after 10 months, 10% after 11 months and 0% after 12 months. The mortality of triatomines that fed on non-treated control dogs was always ≤ 2.5%. CONCLUSIONS Our results suggest that fluralaner (Bravecto®) treatment of dogs induces long-term mortality of T. brasiliensis after the blood meal. This is a potential approach to be used to control vector transmission of T. cruzi, the etiological agent of Chagas disease, especially in endemic areas.
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Affiliation(s)
| | | | - Eduardo Rodrigues de Sena
- Graduate Program in Parasitary Biology, Federal University of Rio Grande Do Norte, Natal, Rio Grande Do Norte, Brazil
| | - Wilo Victor Dos Santos
- Graduate Program in Parasitary Biology, Federal University of Rio Grande Do Norte, Natal, Rio Grande Do Norte, Brazil
| | | | - Vicente Toscano de Araújo-Neto
- Graduate Program in Pharmaceutical Sciences, Federal University of Rio Grande Do Norte, Natal, Rio Grande Do Norte, Brazil
| | - Andressa Noronha Barbosa-Silva
- Graduate Program in Pharmaceutical Sciences, Federal University of Rio Grande Do Norte, Natal, Rio Grande Do Norte, Brazil
| | - Carlos Ramon do Nascimento Brito
- Department of Clinical and Toxicological Analyses, Federal University of Rio Grande Do Norte, Natal, Rio Grande Do Norte, Brazil
| | | | | | - Lúcia Maria da Cunha Galvão
- Department of Clinical and Toxicological Analyses, Federal University of Rio Grande Do Norte, Natal, Rio Grande Do Norte, Brazil
| | - Henrique Rocha de Medeiros
- Agricultural School of Jundiaí, Federal University of Rio Grande Do Norte, Macaíba, Rio Grande Do Norte, Brazil
| | - Antônia Cláudia Jácome da Câmara
- Department of Clinical and Toxicological Analyses, Federal University of Rio Grande Do Norte, Natal, Rio Grande Do Norte, Brazil
| | - Manuela Sales Lima Nascimento
- Department of Microbiology and Parasitology, Federal University of Rio Grande Do Norte, Natal, Rio Grande Do Norte, Brazil
| | - Renata Antonaci Gama
- Department of Microbiology and Parasitology, Federal University of Rio Grande Do Norte, Natal, Rio Grande Do Norte, Brazil
| | - Paulo Marcos Matta Guedes
- Department of Microbiology and Parasitology, Federal University of Rio Grande Do Norte, Natal, Rio Grande Do Norte, Brazil.
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Cardinal MV, Enriquez GF, Macchiaverna NP, Argibay HD, Fernández MDP, Alvedro A, Gaspe MS, Gürtler RE. Long-term impact of a ten-year intervention program on human and canine Trypanosoma cruzi infection in the Argentine Chaco. PLoS Negl Trop Dis 2021; 15:e0009389. [PMID: 33979344 PMCID: PMC8115854 DOI: 10.1371/journal.pntd.0009389] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 04/13/2021] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Interruption of domestic vector-borne transmission of Trypanosoma cruzi is still an unmet goal in several American countries. In 2007 we launched a long-term intervention program aimed to suppress house infestation with the main domestic vector in southern South America (Triatoma infestans) and domestic transmission in Pampa del Indio, a resource-constrained, hyperendemic municipality with 1446 rural houses inhabited by Creole and indigenous people, in the Argentine Chaco ecoregion. Here, we assessed whether the 10-year insecticide-based program combined with community mobilization blocked vector-borne domestic transmission of T. cruzi to humans and dogs. METHODS We carried out two municipality-wide, cross-sectional serosurveys of humans and dogs (considered sentinel animals) during 2016-2017 to compare with baseline data. We used a risk-stratified random sampling design to select 273 study houses; 410 people from 180 households and 492 dogs from 151 houses were examined for antibodies to T. cruzi using at least two serological methods. RESULTS The seroprevalence of T. cruzi in children aged <16 years was 2.5% in 2017 (i.e., 4- to 11-fold lower than before interventions). The mean annual force of child infection (λ) sharply decreased from 2.18 to 0.34 per 100 person-years in 2017. One of 102 children born after interventions was seropositive for T. cruzi; he had lifetime residence in an apparently uninfested house, no outside travel history, and his mother was T. cruzi-seropositive. No incident case was detected among 114 seronegative people of all ages re-examined serologically. Dog seroprevalence was 3.05%. Among native dogs, λ in 2016 (1.21 per 100 dog-years) was 5 times lower than at program onset. Six native adult dogs born after interventions and with stable lifetime residence were T. cruzi-seropositive: three had exposure to T. infestans at their houses and one was an incident case. CONCLUSIONS These results support the interruption of vector-borne transmission of T. cruzi to humans in rural Pampa del Indio. Congenital transmission was the most likely source of the only seropositive child born after interventions. Residual transmission to dogs was likely related to transient infestations and other transmission routes. Sustained vector control supplemented with human chemotherapy can lead to a substantial reduction of Chagas disease transmission in the Argentine Chaco.
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Affiliation(s)
- Marta Victoria Cardinal
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
- * E-mail:
| | - Gustavo Fabián Enriquez
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
| | - Natalia Paula Macchiaverna
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
| | - Hernán Darío Argibay
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
| | - María del Pilar Fernández
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
- Paul G. Allen School for Global Health, Washington State University, Pullman, Washington, United States for America
| | - Alejandra Alvedro
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
| | - María Sol Gaspe
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
| | - Ricardo Esteban Gürtler
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
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Parisi S, Navarro M, Du Plessis JD, Shock JP, Apodaca Michel B, Lucuy Espinoza M, Terán C, Calizaya Tapia NA, Oltmanns K, Baptista Mora A, Saveedra Irala C, Rivera Rojas AA, Rubilar G, Zoller T, Pritsch M. "We have already heard that the treatment doesn't do anything, so why should we take it?": A mixed method perspective on Chagas disease knowledge, attitudes, prevention, and treatment behaviour in the Bolivian Chaco. PLoS Negl Trop Dis 2020; 14:e0008752. [PMID: 33119632 PMCID: PMC7595318 DOI: 10.1371/journal.pntd.0008752] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 08/27/2020] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Chagas disease (CD) is highly endemic in the Bolivian Chaco. The municipality of Monteagudo has been targeted by national interventions as well as by Médecins Sans Frontières to reduce infection rates, and to decentralize early diagnosis and treatment. This study seeks to determine the knowledge and attitudes of a population with increased awareness and to identify remaining factors and barriers for sustained vector control, health care seeking behaviour, and access, in order to improve future interventions. METHODOLOGY/PRINCIPAL FINDINGS A cross-sectional survey was conducted among approximately 10% (n = 669) of the municipality of Monteagudo's households that were randomly selected. Additionally, a total of 14 in-depth interviews and 2 focus group discussions were conducted with patients and key informants. Several attitudes and practices were identified that could undermine effective control against (re-)infection. Knowledge of clinical symptoms and secondary prevention was limited, and revealed specific misconceptions. Although 76% of the participants had been tested for CD, only 18% of those who tested positive concluded treatment with benznidazole (BNZ). Sustained positive serologies after treatment led to perceived ineffectiveness of BNZ. Moreover, access barriers such as direct as well as indirect costs, BNZ stock-outs and a fear of adverse reactions triggered by other community members made patients opt for alternative treatments against CD such as veterinary ivermectin, used by 28% of infected participants in our study. The lack of accessible care for chronic complications as well as socioeconomic consequences, such as the exclusion from both job opportunities and bank loans contributed to the ongoing burden of CD. CONCLUSIONS/SIGNIFICANCE Large scale interventions should be accompanied by operational research in order to identify misconceptions and unintended consequences early on, to generate accessible data for future interventions, and for rigorous evaluation. An integrated, community-based approach tackling social determinants and including both traditional and animal health sectors might help to overcome current barriers and advocate for patients' rights.
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Affiliation(s)
- Sandra Parisi
- Institute of Tropical Medicine and International Health, Charité –Universitätsmedizin Berlin, Berlin, Germany
- DAHW Deutsche Lepra- und Tuberkulosehilfe e. V., Würzburg, Germany
- Department of General Practice, Universitätsklinikum Würzburg, Würzburg, Germany
| | - Miriam Navarro
- Department of Public Health, Science History and Gynecology, Universidad Miguel Hernández, Alicante, Spain
| | | | - Jonathan Phillip Shock
- Department of Maths and Applied Maths, University of Cape Town, Rondebosch, South Africa
| | - Boris Apodaca Michel
- Hospital Dermatológico Monteagudo, Monteagudo, Bolivia
- Fundacion Intercultural NORSUD, Sucre, Bolivia
- DAHW Asociación Alemana de Asistencia al Enfermo con Lepra y Tuberculosis, Oficinas Suramérica, Bogotá, Colombia
| | - Minerva Lucuy Espinoza
- Universidad Mayor, Real y Pontificia de San Francisco Xavier de Chuquisaca, Faculty of Medicine, Sucre, Bolivia
| | - Carolina Terán
- Universidad Mayor, Real y Pontificia de San Francisco Xavier de Chuquisaca, Faculty of Medicine, Sucre, Bolivia
| | | | - Katharina Oltmanns
- DAHW Asociación Alemana de Asistencia al Enfermo con Lepra y Tuberculosis, Oficinas Suramérica, Bogotá, Colombia
| | - Abundio Baptista Mora
- Fundacion Intercultural NORSUD, Sucre, Bolivia
- DAHW Asociación Alemana de Asistencia al Enfermo con Lepra y Tuberculosis, Oficinas Suramérica, Bogotá, Colombia
- Universidad Mayor, Real y Pontificia de San Francisco Xavier de Chuquisaca, Faculty of Medicine, Sucre, Bolivia
| | - Claudia Saveedra Irala
- Hospital Dermatológico Monteagudo, Monteagudo, Bolivia
- Fundacion Intercultural NORSUD, Sucre, Bolivia
- DAHW Asociación Alemana de Asistencia al Enfermo con Lepra y Tuberculosis, Oficinas Suramérica, Bogotá, Colombia
| | - Angel Alberto Rivera Rojas
- DAHW Asociación Alemana de Asistencia al Enfermo con Lepra y Tuberculosis, Oficinas Suramérica, Bogotá, Colombia
| | - Gonzalo Rubilar
- DAHW Asociación Alemana de Asistencia al Enfermo con Lepra y Tuberculosis, Oficinas Suramérica, Bogotá, Colombia
| | - Thomas Zoller
- Charité –Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Department of Infectious Diseases and Respiratory Medicine, Charité –Universitätsmedizin Berlin, Berlin, Germany
| | - Michael Pritsch
- Division of Infectious Diseases and Tropical Medicine, LMU University Hospital Munich, Munich, Germany
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