1
|
Encinas M, Ferrara Muñiz X, Sammarruco RA, Ruiz Menna V, Garro CJ, Delgado F, Macías A, Magnano G, Zumárraga MJ, Garbaccio SG, Eirin ME. Limited usefulness of the IS 6110 touchdown-PCR in blood for tuberculin skin test false-negative cattle with serological response to Mycobacterium bovis. Front Vet Sci 2024; 11:1359205. [PMID: 38835898 PMCID: PMC11149419 DOI: 10.3389/fvets.2024.1359205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 04/23/2024] [Indexed: 06/06/2024] Open
Abstract
Ante-mortem diagnosis of bovine tuberculosis (bTB) is based mainly on the tuberculin skin test (TST) and the ɣ-IFN release assay (IGRA). Some infected animals escape screening tests, thus, limit herd sanitation. Previous reports have suggested a predominant pattern of multi-organ lesions attributable to Mycobacterium bovis (the causative agent of bTB) bacteraemia. A case-control study was conducted to investigate blood PCR as an alternative tool for improving ante-mortem detection of TST false-negative bovines. Cases comprised 70 TST false-negative bovines (cases), which were serology positive, and controls included 81 TST positive bovines; all of them confirmed as infected with M. bovis. Detection of the IS6110 target through touchdown blood-PCR (IS6110 TD-PCR) was performed. The positivity of the blood-PCR was 27.2% in the control group. This performance was similar to the 15% obtained among cases (p = 0.134). Most cases identified by the IS6110 TD-PCR exhibited focalized lesions (p = 0.002). Results demonstrated that blood-PCR could detect TST false-negative cattle, even if they are negative for IGRA. Considering that cases exhibited humoral response to M. bovis, further studies conducted in a pre-serological stage could provide evidence about the real contribution of the technique in herds.
Collapse
Affiliation(s)
- Micaela Encinas
- Instituto de Agrobiotecnología y Biología Molecular (IABiMo) UEDD CONICET-INTA, Centro de Investigación en Ciencias Veterinarias y Agronómicas (CICVyA)-CNIA, Hurlingham, Argentina
| | - Ximena Ferrara Muñiz
- Instituto de Agrobiotecnología y Biología Molecular (IABiMo) UEDD CONICET-INTA, Centro de Investigación en Ciencias Veterinarias y Agronómicas (CICVyA)-CNIA, Hurlingham, Argentina
| | - Romina Ayelén Sammarruco
- Instituto de Patobiología Veterinaria (IPVET), UEDD CONICET-INTA, Instituto Nacional de Tecnología Agropecuaria (INTA), INTA-CONICET, Hurlingham, Argentina
| | - Victoria Ruiz Menna
- Instituto de Patobiología Veterinaria (IPVET), UEDD CONICET-INTA, Instituto Nacional de Tecnología Agropecuaria (INTA), INTA-CONICET, Hurlingham, Argentina
| | - Carlos Javier Garro
- Instituto de Patobiología Veterinaria (IPVET), UEDD CONICET-INTA, Instituto Nacional de Tecnología Agropecuaria (INTA), INTA-CONICET, Hurlingham, Argentina
| | - Fernando Delgado
- Instituto de Patobiología Veterinaria (IPVET), UEDD CONICET-INTA, Instituto Nacional de Tecnología Agropecuaria (INTA), INTA-CONICET, Hurlingham, Argentina
| | - Analía Macías
- Departamento de Patología Animal, Facultad de Agronomía y Veterinaria, Universidad Nacional de Río Cuarto, Río Cuarto, Argentina
| | - Gabriel Magnano
- Departamento de Patología Animal, Facultad de Agronomía y Veterinaria, Universidad Nacional de Río Cuarto, Río Cuarto, Argentina
| | - Martín José Zumárraga
- Instituto de Agrobiotecnología y Biología Molecular (IABiMo) UEDD CONICET-INTA, Centro de Investigación en Ciencias Veterinarias y Agronómicas (CICVyA)-CNIA, Hurlingham, Argentina
| | - Sergio Gabriel Garbaccio
- Instituto de Patobiología Veterinaria (IPVET), UEDD CONICET-INTA, Instituto Nacional de Tecnología Agropecuaria (INTA), INTA-CONICET, Hurlingham, Argentina
| | - María Emilia Eirin
- Instituto de Agrobiotecnología y Biología Molecular (IABiMo) UEDD CONICET-INTA, Centro de Investigación en Ciencias Veterinarias y Agronómicas (CICVyA)-CNIA, Hurlingham, Argentina
| |
Collapse
|
2
|
Talebzadeh F, Ghadipasha M, Gharehdaghi J, Raoofian R, Azam K, Koosha M, Oshaghi MA. Efficiency of mitochondrial genes and nuclear Alu elements in detecting human DNA in blood meals of Anopheles stephensi mosquitoes: a time-course study. Parasit Vectors 2023; 16:284. [PMID: 37580774 PMCID: PMC10426119 DOI: 10.1186/s13071-023-05884-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 07/14/2023] [Indexed: 08/16/2023] Open
Abstract
BACKGROUND The time required for PCR detection of DNA in human blood meals in vector mosquitoes may vary, depending on the molecular markers used, based on the size and copy number of the amplicons. Detailed knowledge of the blood-feeding behavior of mosquito populations in nature is an essential component for evaluating their vectorial capacity and for assessing the roles of individual vertebrates as potential hosts involved in the transmission of vector-borne diseases. METHODS Laboratory experiments were conducted to compare the time course of PCR detection of DNA in human blood meals from individual blood-fed Anopheles stephensi mosquitoes, using loci with different characteristics, including two mitochondrial DNA (mtDNA) genes, cytB (228 bp) and 16S ribosomal RNA (rRNA) (157 bp) and nuclear Alu-repeat elements (226 bp) at different time points after the blood meal. RESULTS Human DNA was detectable up to 84-120 h post-blood-feeding, depending on the length and copy number of the loci. Our results suggest that 16S rRNA and Alu-repeat markers can be successfully recovered from human DNA up to 5 days post-blood-meal. The 16S rDNA and Alu-repeat loci have a significantly (P = 0.008) slower decline rate than the cytB locus. Median detection periods (T50) for the amplicons were 117, 113 and 86.4 h for Alu-repeat, 16S rDNA and cytB, respectively, suggesting an inverse linear relationship between amplicon size/copy number and digestion time. CONCLUSION This comparative study shows that the Alu-repeat locus is the most efficient marker for time-course identification of human DNA from blood meals in female mosquitoes. It is also a promising tool for determining the anthropophilic index (AI) or human blood index (HBI), i.e. the proportion of blood meals from humans, which is often reported as a relative measure of anthropophagy of different mosquito vectors, and hence a measure of the vector competence of mosquito species collected in the field.
Collapse
Affiliation(s)
- Fahimeh Talebzadeh
- Department of Vector Biology and Control of Diseases, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoud Ghadipasha
- Legal Medicine Research Center, Legal Medicine Organization, Tehran, Iran
| | - Jaber Gharehdaghi
- Legal Medicine Research Center, Legal Medicine Organization, Tehran, Iran
| | - Reza Raoofian
- Legal Medicine Research Center, Legal Medicine Organization, Tehran, Iran
| | - Kamal Azam
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mona Koosha
- Department of Vector Biology and Control of Diseases, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Ali Oshaghi
- Department of Vector Biology and Control of Diseases, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
| |
Collapse
|
3
|
Izenour K, Zohdy S, Kalalah A, Starkey L, Blagburn B, Sundermann C, Salib F. Detection of zoonotic vector-borne pathogens in domestic dogs in Giza, Egypt. Vet Parasitol Reg Stud Reports 2022; 32:100744. [PMID: 35725107 DOI: 10.1016/j.vprsr.2022.100744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 04/15/2022] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
The public health implications of zoonotic vector-borne pathogens are numerous because domestic animals, such as dogs, live in close proximity to humans. Blood was collected from 116 domestic dogs in Cairo, Egypt from three different settings at the human-animal interface. The three settings the dogs came from were: privately owned animals seeking care at the Cairo University Faculty of Veterinary Medicine Clinic, non-laboratory reared research dogs maintained at the Cairo University Faculty of Veterinary Medicine, and an urban private animal rescue in Shabramont, Giza, Egypt. Enrolled animals were visually inspected for presence of flea or tick ectoparasites, Rhipicephalus sanguineus sensu lato ticks were recovered from 56 enrolled animals and a flea identified as Ctenocephalides felis was recovered from one animal. To test for past and/or current infection with vector-borne pathogens, conventional PCR and IDEXX SNAP® 4Dx® Plus were performed on whole blood. Pathogen targets included: Anaplasma spp., Ehrlichia spp., Babesia spp., Borrelia spp., Bartonella spp., Dirofilaria spp., and Rickettsia spp. Among dogs sampled across all locations, one dog was positive for Babesia sp. infection and one dog was positive for Anaplasma sp. infection as detected by PCR and confirmed by Sanger sequencing. Three additional dogs were positive for infection but had incomplete sequences obtained: two for Ehrlichia sp. and one for Borrelia sp. The SNAP® test results for all sampled dogs included: eight dogs positive for Anaplasma spp., 14 dogs positive for Ehrlichia spp., and five additional dogs positive for both Anaplasma spp. and Ehrlichia spp. SNAP® test results by sampling location showed that 66% of the dogs at the animal rescue were positive for Anaplasma spp. and/or Ehrlichia spp., 17% of the privately owned dogs at the Faculty of Veterinary medicine were positive for Anaplasma spp. and/or Ehrlichia spp., and none of the research dogs were positive for any of the targets on the SNAP® test. This high proportion of seropositivity in the animals sampled indicates a vector population which is not well controlled and a need for continued owner education and promotion of consistent use of preventive medications and the risk for zoonotic transmission.
Collapse
Affiliation(s)
- Katie Izenour
- Department of Pathobiology, Auburn University College of Veterinary Medicine, 166 Greene Hall Auburn, AL 36849, United States of America.
| | - Sarah Zohdy
- Department of Pathobiology, Auburn University College of Veterinary Medicine, 166 Greene Hall Auburn, AL 36849, United States of America; College of Forestry, Wildlife and Evironment, Auburn University, 600 Duncan Drive, AL 36849, United States of America
| | - Anwar Kalalah
- Department of Pathobiology, Auburn University College of Veterinary Medicine, 166 Greene Hall Auburn, AL 36849, United States of America
| | - Lindsay Starkey
- Department of Pathobiology, Auburn University College of Veterinary Medicine, 166 Greene Hall Auburn, AL 36849, United States of America
| | - Byron Blagburn
- Department of Pathobiology, Auburn University College of Veterinary Medicine, 166 Greene Hall Auburn, AL 36849, United States of America
| | - Christine Sundermann
- Department of Biological Sciences, Auburn University College of Science and Mathematics, 101 Rouse Life Sciences Building Auburn, AL 36849, United States of America
| | - Fayez Salib
- Cairo University, Faculty of Veterinary Medicine, Giza Governorate, Cairo, Egypt
| |
Collapse
|
4
|
Surveillance of Trypanosoma cruzi infection in Triatomine vectors, feral dogs and cats, and wild animals in and around El Paso county, Texas, and New Mexico. PLoS Negl Trop Dis 2021; 15:e0009147. [PMID: 33600455 PMCID: PMC7924784 DOI: 10.1371/journal.pntd.0009147] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 03/02/2021] [Accepted: 01/14/2021] [Indexed: 01/03/2023] Open
Abstract
The causative agent of Chagas disease, Trypanosoma cruzi, is transmitted by triatomine vectors. The insect is endemic in the Americas, including the United States, where epidemiological studies are limited, particularly in the Southwestern region. Here, we have determined the prevalence of T. cruzi in triatomines, feral cats and dogs, and wild animals, the infecting parasite genotypes and the mammalian host bloodmeal sources of the triatomines at four different geographical sites in the U.S.-Mexico border, including El Paso County, Texas, and nearby cities in New Mexico. Using qualitative polymerase chain reaction to detect T. cruzi infections, we found 66.4% (n = 225) of triatomines, 45.3% (n = 95) of feral dogs, 39.2% (n = 24) of feral cats, and 71.4% (n = 7) of wild animals positive for T. cruzi. Over 95% of T. cruzi genotypes or discrete typing units (DTUs) identified were TcI and some TcIV. Furthermore, Triatoma rubida was the triatomine species most frequently (98.2%) collected in all samples analyzed. These findings suggest a high prevalence of T. cruzi infections among triatomines, and feral and wild animals in the studied sites. Therefore, our results underscore the urgent need for implementation of a systematic epidemiological surveillance program for T. cruzi infections in insect vectors, and feral and wild animals, and Chagas disease in the human population in the southwestern region of the United States. Chagas disease is caused by the parasite Trypanosoma cruzi and one of the major transmission routes is the contaminated feces of blood-feeding triatomine insect vectors, popularly known as kissing bugs. In recent years, this disease has become an important public health concern to the United States and other nonendemic regions of the world. Despite many studies about the prevalence of T. cruzi in triatomines, and domestic, feral and wild animals in central and southern Texas, there have been no studies in west Texas and New Mexico. In this study, we report the presence of triatomines in residences in El Paso County, TX, and surrounding communities in New Mexico (cities of Anthony and Las Cruces), as well as T. cruzi infections in feral and wild animals. Using two molecular techniques to analyze the bloodmeal source in triatomines, we detected 12 different mammalian bloodmeal sources, including human and canine. Finally, parasite genotyping showed that most (95%) of the samples belonged to the genotype TcI, which is prevalent in North America. Our findings indicate that the El Paso County and surrounding communities (>950,000 people) are high risk areas for T. cruzi transmission to humans, feral cats and dogs, and wild animals. Thus, there is an urgent necessity for a public health epidemiological surveillance program for T. cruzi infections in kissing bugs, feral and wild animals, and in the human population in the U.S.-Mexico border region.
Collapse
|
5
|
Kipp EJ, de Almeida M, Marcet PL, Bradbury RS, Benedict TK, Lin W, Dotson EM, Hergert M. An Atypical Case of Autochthonous Cutaneous Leishmaniasis Associated with Naturally Infected Phlebotomine Sand Flies in Texas, United States. Am J Trop Med Hyg 2020; 103:1496-1501. [PMID: 32618254 DOI: 10.4269/ajtmh.20-0107] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
In the United States, phlebotomine sand flies carrying Leishmania (Leishmania) mexicana are endemic along the southern border. However, relatively little is known about the enzootic and zoonotic transmission of L. (L.) mexicana within the United States, and autochthonous cases of the consequent disease are rarely reported. We investigated an atypical case of cutaneous leishmaniasis (CL) caused by L. (L.) mexicana in a patient from central Texas which did not respond to a typical antileishmanial chemotherapy. We also investigated sand fly vectors around the patient's residence. PCR followed by DNA sequencing was used for determination of Leishmania spp., sand fly species, and host blood meal source. The L. (L.) mexicana genotype from the patient was identical to one found in a positive sand fly. Moreover, this genotype presented the same single-nucleotide polymorphisms as other historical CL cases acquired in Texas over the last 10 years, but distinct from those originating in Mexico and Central America. Three sand fly species were identified among the samples analyzed (n = 194), the majority of which were Lutzomyia (Dampfomyia) anthophora (n = 190), of which four specimens tested positive for Leishmania and two blood-fed specimens showed the presence of a human blood meal. This study highlights the complexity of clinical management of CL in a setting where the disease is infrequently encountered. The detection of human blood in Lu. (D.) anthophora is the first documentation of anthropophagy in this species. This is the first report of wild-caught, naturally infected sand flies found in association with an autochthonous case of human leishmaniasis and the specific strain of Leishmania (Leishmania) mexicana in the United States.
Collapse
Affiliation(s)
- Evan J Kipp
- College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota.,Texas Department of State Health Services, Zoonosis Control Program, Temple, Texas
| | - Marcos de Almeida
- Parasitic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Paula L Marcet
- Entomology Branch/DPDM/Centers for Disease Control and Prevention (CDC), Atlanta, Georgia
| | - Richard S Bradbury
- School of Health and Life Sciences, Federation University, Victoria, Australia.,Parasitic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Theresa K Benedict
- Parasitic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Wuling Lin
- IHRC Inc., Atlanta, Georgia.,Parasitic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Ellen M Dotson
- Entomology Branch/DPDM/Centers for Disease Control and Prevention (CDC), Atlanta, Georgia
| | - Melinda Hergert
- Texas Department of State Health Services, Zoonosis Control Program, Temple, Texas.,Texas Animal Health Commission, Austin, Texas
| |
Collapse
|
6
|
Fraenkel S, Salvioni OD, de Arias AR, Arze VP, Rolón M, Ramirez N, Vega Gómez C. Identification of bloodmeal sources of triatomines captured in the Paraguayan Chaco region of South America by means of molecular biology analysis. Pathog Glob Health 2020; 114:30-39. [PMID: 31973639 DOI: 10.1080/20477724.2020.1716558] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The Paraguayan Chaco is an isolated environment with its own unique ecosystem. In this region, Chagas disease remains a health problem. Chagas disease is caused by the parasite Trypanosoma cruzi, and it is primarily transmitted by triatomines. In order to identify the blood meal sources of triatomines, specimens of the vector were collected in domestic and peridomestic areas and the PCR-RFLP method was implemented. Cytochrome b was amplified from the samples and later subjected to digestion with two restriction enzymes: Hae III and Xho I.It was possible to generate distinct restriction patterns on the amplified material to identify several blood meal sources for the vectors. We employed the blood from several species as positive controls: human, chicken, canine, feline, and armadillo blood. However, we identified only 3 sources for the blood meals of the insect vectors: human, chicken and canine blood. In total, 76 triatomines were captured. T. cruzi was not found in any of them. In 61% of the captured specimens, the blood meal sources for the vectors could be identified. In 30% of these cases, the presence of DNA from more than one vertebrate was detected in the same triatomine. The most common blood meal source found was chicken blood. The presence of human and chicken blood in triatomines captured in domestic and peridomestic areas strongly suggests that the parasite can freely move amongst both areas regardless of food availability. Free vector movement in these areas constitutes an epidemiological threat for the inhabitants of the community under study.
Collapse
Affiliation(s)
- Stefanía Fraenkel
- Laboratorio de Biología Molecular, Centro para el Desarrollo de la Investigación Científica, Asunción, Paraguay
| | - Oscar Daniel Salvioni
- Laboratorio de Biología Molecular, Centro para el Desarrollo de la Investigación Científica, Asunción, Paraguay
| | - Antonieta Rojas de Arias
- Laboratorio de Biología Molecular, Centro para el Desarrollo de la Investigación Científica, Asunción, Paraguay
| | - Verónica Paola Arze
- Laboratorio de Biología Molecular, Centro para el Desarrollo de la Investigación Científica, Asunción, Paraguay
| | - Miriam Rolón
- Laboratorio de Biología Molecular, Centro para el Desarrollo de la Investigación Científica, Asunción, Paraguay
| | - Natalia Ramirez
- Laboratorio de Biología Molecular, Centro para el Desarrollo de la Investigación Científica, Asunción, Paraguay
| | - Celeste Vega Gómez
- Laboratorio de Biología Molecular, Centro para el Desarrollo de la Investigación Científica, Asunción, Paraguay
| |
Collapse
|
7
|
Levine RS, Mead DG, Hamer GL, Brosi BJ, Hedeen DL, Hedeen MW, McMillan JR, Bisanzio D, Kitron UD. Supersuppression: Reservoir Competency and Timing of Mosquito Host Shifts Combine to Reduce Spillover of West Nile Virus. Am J Trop Med Hyg 2016; 95:1174-1184. [PMID: 27503511 DOI: 10.4269/ajtmh.15-0809] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 06/09/2016] [Indexed: 11/07/2022] Open
Abstract
In the eastern United States, human cases of West Nile virus (WNV) result from spillover from urban epizootic transmission between passerine birds and Culex mosquitoes. In Atlanta, GA, substantial WNV presence in hosts and vectors has not resulted in the human disease burden observed in cities with similar infection pressure. Our study goal was to investigate extrinsic ecological conditions that potentially contribute to these reduced transmission rates. We conducted WNV surveillance among hosts and vectors in urban Atlanta and recorded an overall avian seroprevalence of nearly 30%, which was significantly higher among northern cardinals, blue jays, and members of the mimid family, and notably low among American robins. Examination of temporal Culex feeding patterns showed a marked feeding shift from American robins in the early season to northern cardinals in the late season. We therefore rule out American robins as superspreaders in the Atlanta area and suggest instead that northern cardinals and mimids act as WNV "supersuppressor" species, which slow WNV transmission by drawing many infectious bites during the critical virus amplification period, yet failing to amplify transmission due to low host competencies. Of particular interest, urban forest patches provide spillover protection by increasing the WNV amplification fraction on supersuppressor species.
Collapse
Affiliation(s)
- Rebecca S Levine
- Department of Environmental Sciences, Emory University, Atlanta, Georgia.
| | - Daniel G Mead
- Southeastern Cooperative Wildlife Disease Study, University of Georgia College of Veterinary Medicine, Athens, Georgia
| | - Gabriel L Hamer
- Department of Entomology, Texas A&M College of Agriculture and Life Sciences, Texas A&M University, College Station, Texas
| | - Berry J Brosi
- Department of Environmental Sciences, Emory University, Atlanta, Georgia
| | - David L Hedeen
- Office of Environmental Services, Georgia Department of Transportation, Atlanta, Georgia
| | - Meghan W Hedeen
- Office of Environmental Services, Georgia Department of Transportation, Atlanta, Georgia
| | - Joseph R McMillan
- Department of Environmental Sciences, Emory University, Atlanta, Georgia
| | - Donal Bisanzio
- Department of Environmental Sciences, Emory University, Atlanta, Georgia
| | - Uriel D Kitron
- Department of Environmental Sciences, Emory University, Atlanta, Georgia
| |
Collapse
|
8
|
Valença-Barbosa C, Lima MM, Sarquis O, Bezerra CM, Abad-Franch F. Modeling disease vector occurrence when detection is imperfect II: Drivers of site-occupancy by synanthropic Triatoma brasiliensis in the Brazilian northeast. PLoS Negl Trop Dis 2014; 8:e2861. [PMID: 24811125 PMCID: PMC4014420 DOI: 10.1371/journal.pntd.0002861] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 03/28/2014] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Understanding the drivers of habitat selection by insect disease vectors is instrumental to the design and operation of rational control-surveillance systems. One pervasive yet often overlooked drawback of vector studies is that detection failures result in some sites being misclassified as uninfested; naïve infestation indices are therefore biased, and this can confound our view of vector habitat preferences. Here, we present an initial attempt at applying methods that explicitly account for imperfect detection to investigate the ecology of Chagas disease vectors in man-made environments. METHODOLOGY We combined triplicate-sampling of individual ecotopes (n = 203) and site-occupancy models (SOMs) to test a suite of pre-specified hypotheses about habitat selection by Triatoma brasiliensis. SOM results were compared with those of standard generalized linear models (GLMs) that assume perfect detection even with single bug-searches. PRINCIPAL FINDINGS Triatoma brasiliensis was strongly associated with key hosts (native rodents, goats/sheep and, to a lesser extent, fowl) in peridomestic environments; ecotope structure had, in comparison, small to negligible effects, although wooden ecotopes were slightly preferred. We found evidence of dwelling-level aggregation of infestation foci; when there was one such focus, same-dwelling ecotopes, whether houses or peridomestic structures, were more likely to become infested too. GLMs yielded negatively-biased covariate effect estimates and standard errors; both were, on average, about four times smaller than those derived from SOMs. CONCLUSIONS/SIGNIFICANCE Our results confirm substantial population-level ecological heterogeneity in T. brasiliensis. They also suggest that, at least in some sites, control of this species may benefit from peridomestic rodent control and changes in goat/sheep husbandry practices. Finally, our comparative analyses highlight the importance of accounting for the various sources of uncertainty inherent to vector studies, including imperfect detection. We anticipate that future research on infectious disease ecology will increasingly rely on approaches akin to those described here.
Collapse
Affiliation(s)
- Carolina Valença-Barbosa
- Chagas Disease Eco-epidemiology Laboratory, Instituto Oswaldo Cruz – Fiocruz, Rio de Janeiro, Brazil
| | - Marli M. Lima
- Chagas Disease Eco-epidemiology Laboratory, Instituto Oswaldo Cruz – Fiocruz, Rio de Janeiro, Brazil
| | - Otília Sarquis
- Chagas Disease Eco-epidemiology Laboratory, Instituto Oswaldo Cruz – Fiocruz, Rio de Janeiro, Brazil
| | | | - Fernando Abad-Franch
- Infectious Disease Ecology Laboratory, Instituto Leônidas e Maria Deane – Fiocruz, Manaus, Brazil
- * E-mail:
| |
Collapse
|