Seropositive Dogs Research Articles

Serological survey of anti-Leptospira spp. antibodies in individuals with animal hoarding disorder and their dogs in a major city of Southern Brazil.

BackgroundIndividuals with hoarding disorder (HD) presented a persistent difficulty in detaching from objects and/or animals. Unhealthy conditions, frequently found in cases of animal HD (AHD), may favour environmental contamination and the spread of zoonotic pathogens. Despite that, only one study of zoonotic diseases in individuals with AHD and their companion animals has been conducted to date.ObjectivesThis study aimed to assess the seroprevalence of anti‐Leptospira spp. antibodies in individuals with AHD and their dogs in a major city of Southern Brazil.MethodsBlood samples were obtained from 264 dogs (21 households) and 19 individuals with AHD (11 households) and tested by microscopic agglutination test.ResultsAll human samples were seronegative. Seropositivity was found in 16/264 (6.1%; CI 95% 3.3–9.6%) dogs from 11/21 (52.38%) households, with titres ranging from 100 up to 400, and Copenhageni (10/16; 62.5%) was the most frequent serovar. Surprisingly, seropositivity of hoarded dogs found herein was among the lowest reportedly observed in other dog populations of Brazil. Two epidemiological variables were significantly associated with seropositivity in dogs: the presence of cat hoarding (p = 0.004) and the report of flood occurrence in the household (p = 0.031).ConclusionsNo individuals with AHD were seropositive, and besides the lower seroprevalence of dogs, they probably had contact with Leptospira spp. at some point in their life. Since dogs can be considered potential sentinels in leptospirosis, public health programs must become aware of the risk of leptospirosis cases in households of individuals with AHD and nearby communities.

A serosurvey for spotted fever group Rickettsia and Coxiella burnetii antibodies in rural dogs and foxes, Chile

Antibodies against Spotted Fever Group (SFG) Rickettsia and Coxiella burnetii, investigated through indirect antibody immunofluorescence tests, were detected in serum samples from 3.1% and 0% of 358 rural dogs, respectively, and in none of 32 wild foxes tested. SFG Rickettsia seropositive dogs were only detected in the Mountain Desert (8%) and the Steppe-Mediterranean (9%) regions. Exposure in the Mountain Desert, where no ticks and fleas were found on any dog, could correspond to a new SFG Rickettsia sp. recently described in soft ticks or to a related agent. Our survey confirms low endemicity in the country of C. burnetii, as observed in recent serosurveys in humans.

Conjunctival Swab Real Time-PCR in Leishmania infantum Seropositive Dogs: Diagnostic and Prognostic Values.

Conjunctival swabs (CS) are the most promising non-invasive samples for the diagnosis and the regular screening of Leishmania infantum infection in dogs although knowledge on their diagnostic performance is still inconclusive. This study evaluates CS real time-PCR (qPCR) analysis for the diagnosis of canine leishmaniosis (CanL) and its prognostic value in seropositive dogs from an endemic area. In October 2020 (T0), 26 dogs were enrolled, divided in two groups according to anti-L. infantum antibody titres (n = 13, group low titre (LT) and n = 13, group high titre (HT)), and followed-up in August 2021. At both timepoints, animals underwent clinical examination, complete blood count and biochemical analyses, and serological (indirect fluorescent antibody test) and molecular (CS and peripheral blood qPCR) testing. At T0, 10 out of 26 enrolled dogs were positive at CS qPCR, with the number of positive animals significantly higher in group HT than in LT. After 10 months, only 5 out of 21 dogs that completed the trial still tested CS qPCR positive, and none of them developed an active CanL based on clinical score and antibody titre. None of the dogs required any leishmanicidal and/or leishmaniostatic treatments. This prospective study showed unsatisfying diagnostic and prognostic performances of CS qPCR analysis in L. infantum seropositive asymptomatic dogs from an endemic area.

Impact of vector control actions in the abundance of Lutzomyia longipalpis in Montes Claros, Brazil

Visceral leishmaniasis (VL) is endemic to many states in Brazil. To prevent further expansion of the disease, the Brazilian Ministry of Health adopted integrated measures through the Program of Surveillance and Control of Visceral Leishmaniasis (PSCVL), whose actions include the diagnosis and euthanasia of seropositive dogs (the main domestic reservoirs), the use of residual insecticides, environmental management (EM) to control vector population (mainly Lutzomyia longipalpis phlebotomine), rigorous epidemiological surveillance, and health education. The present study was conducted in areas with recent moderate VL transmission to evaluate the efficacy of vector control activities. The systematic capture of phlebotomine was performed for three consecutive days per month, from August 2015 to July 2017. The number of specimens captured was taken as a representative of the monthly insect population. A total of 38,055 phlebotomine specimens were captured and identified at the species level. Lu. longipalpis was consistently found to be the predominant species (97.7%) each month. In the first year of the study, no intervention was performed. In the second year, two cycles of chemical spraying, EM, or a combination of both were performed before and after the rainy season. All interventions, either individually or in combination, reduced the abundance of Lu. longipalpis in the study area.

Seroprevalence and hematological abnormalities associated with Ehrlichia canis in dogs referred to a veterinary teaching hospital in central-western Brazil

ABSTRACT: Ticks are significant parasites of dogs in the tropics, where tick-borne pathogens are highly prevalent, especially in areas where tick control measures are frequently neglected. This study investigated the seroprevalence and hematological abnormalities associated with Ehrlichia canis in dogs referred to a veterinary teaching hospital in Central-western Brazil. Out of 264 dogs tested for anti-Ehrlichia canis antibodies by an indirect immunofluorescence assay (IFA), 59.1% (156/264) were positive. Seropositivity was significantly associated to anemia and thrombocytopenia, alone or in combination, and to leukopenia. Conversely, there were no differences in terms of seroprevalence according to sex, breed and age. This study demonstrated that dogs referred to a veterinary teaching hospital in Central-western Brazil are highly exposed to E. canis and that seropositive dogs are more likely to present hematological abnormalities, particularly anemia, thrombocytopenia and leukopenia. To our knowledge, this is the first study on detection of anti-E. canis antibodies by means of IFA among dogs in the state of Goiás. These findings highlighted the need for increasing awareness among dog owners regarding tick control measures in Central-western Brazil, ultimately to reduce the risk of exposure to E. canis and other tick-borne pathogens.

A serological survey of canine leptospirosis in the city of Belgrade, Serbia

Canine leptospirosis is a zoonosis caused by bacteria belonging to the genus Leptospira. Dogs are one of the animal species involved in the cycle of preservation and transmission of leptospirosis in urban areas. Serological testing for the presence of specific antibodies against Leptospira spp. in dogs was continuously performed between 2010 and 2020 in the city of Belgrade. At the request of the owners themselves, other veterinary laboratories or laboratory clinics, 179 blood sera from 179 dogs were examined in the Laboratory for Immunology, Scientific Institute of Veterinary Medicine of Serbia. Blood sera samples from dogs were examined using the standard microscopic agglutination test (MAT) for the presence of specific antibodies against seven different serovars of Leptospira: Pomona, Icterohaemorrhagiae, Grippotyphosa, Sejroe, Canicola, Bataviae, and Australis. The number of seropositive dogs was 17/179 (9.5%). Among all examined sera, the highest titre of seropositive samples was to serovar Icterohaemorrhagiae (10/17, 58.8%), followed by Pomona (4/17, 23.5%), and serovar Canicola (3/17, 17.6%). Specific antibodies for serovars Grippotyphosa, Sejroe, Bataviae and Australis were not detected in any of the dog sera. Cross-reaction (the presence of two or three titres with different values where one of them was higher than others) between different serovars was diagnosed in a low number of sera (n=4), with the following serovars: Icterohaemorrhagiae and Pomona (n=3) and Pomona and Canicola (n=1). The confirmed specific antibody titres for Leptospira spp. were between 1:100 to 1:3000 (5 sera had titres of 1:100, 7 had titres of 1:300, 4 had titres of 1:1000, and 1 serum had a titre 1:3000). Monitoring canine leptospirosis is a useful tool in preventing leptospirosis in Belgrade.

Seroprevalence of Anaplasma spp. and Ehrlichia spp. and molecular detection of Anaplasma phagocytophilum and Anaplasma platys in stray dogs in Bosnia and Herzegovina

Stray dogs may be highly exposed to vector-borne pathogens (VBPs), including zoonotic agents, and therefore may pose a high risk of spreading infections to other animals and humans. Among the Anaplasmataceae, Anaplasma phagocytophilum, A. platys and Ehrlichia canis are commonly identified species in dogs in Europe; however, information on the occurrence of these pathogens in canine populations from Bosnia and Herzegovina (B&H) is still lacking. Thus, the aim of this study was to determine the seroprevalence of Anaplasma spp. and Ehrlichia spp. in stray dogs in the Sarajevo region of B&H and to identify A. phagocytophilum, A. platys, E. canis and E. ewingii by molecular techniques. A total of 903 blood samples of stray dogs were screened by SNAP 4Dx Plus Test for the presence of antibodies against A. phagocytophilum/A. platys and E. canis/E. ewingii. Real-time PCR assays were performed for the detection of Anaplasmataceae, A. phagocytophilum, A. platys, E. canis and E. ewingii in seropositive dogs. Antibodies to A. phagocytophilum/A. platys and/or E. canis/E. ewingii were detected in 187 (20.7%) samples. Seroprevalence was highest for A. phagocytophilum/A. platys (184/903, 20.4%). Two dogs had antibodies to E. canis/E. ewingii, while one dog was found to have antibodies to A. phagocytophilum/A. platys and to E. canis/E. ewingii. Forty-eight (25.7%) of the 187 seropositive dogs examined by Real-time PCR were positive for Anaplasmataceae. A. phagocytophilum was detected in 45 (24%) samples, while one sample was positive for A. phagocytophilum and A. platys. Two samples positive for Anaplasmataceae tested negative in the species-specific PCRs. E. canis or E. ewingii could not be detected in any of the Ehrlichia-seropositive dogs. These findings highlight the need for dog health monitoring, improving the health and welfare of stray dog population, and establishment of effective surveillance systems to combat VBDs.

Brucella suis Seroprevalence and Associated Risk Factors in Dogs in Eastern Australia, 2016 to 2019

Brucella suis is a zoonotic disease of feral pigs that also affects pig hunting dogs, pig hunters, veterinarians and veterinary staff. In recent years the incidence of B. suis in the eastern Australian states of New South Wales (NSW) and Queensland (QLD) has increased. A cross-sectional study was conducted to document the seroprevalence, geographical extent and risk factors for B. suis in dogs at-risk of contracting the disease. Eligible dogs were those that were known to hunt or consume feral pig meat. Dogs were enrolled through private veterinary clinics and/or directly by District Veterinarians in six regions of NSW and QLD. Blood was collected by venepuncture and tested for B. suis antibodies using the Rose Bengal Test (RBT) followed by a Complement Fixation Test (CFT) if they returned a positive RBT. Owners were invited to complete a questionnaire on the dogs' signalment, husbandry including hunting practices and locations, and any clinical signs referable to brucellosis. Of the 317 dogs included in the prevalence survey, 21 were seropositive returning a survey-adjusted true seroprevalence of 9.3 (95% CI 0.45 to 18) B. suis positive dogs per 100 dogs at-risk. True seroprevalence ranged from 0 to 24 B. suis positive dogs per 100 across eastern Australia, with the highest prevalence in central west NSW and southern QLD. Adjusted for other factors, dogs that shared a household with other seropositive dogs and those that traveled away from their home regions to hunt were more likely to be seropositive. Clinical signs at presentation were not predictive of serostatus, with seropositive and seronegative dogs equally likely to present with signs consistent with brucellosis. The results obtained from this study show that B. suis exposure is relatively common in dogs that have contact with feral pigs, with one in 10 testing seropositive. Further studies are needed to understand the progression and risk of transmission from seropositive dogs.

Is the Prevalence of Leishmania infantum Linked to Breeds in Dogs? Characterization of Seropositive Dogs in Ibiza.

Simple SummaryLeishmaniosis is an important zoonotic protozoan disease. Leishmania infantum is a protozoan species that accounts for the majority of cases in the Mediterranean. In this study, we analyzed the prevalence of infection in different dog breeds from Ibizan Island. Our results showed that the Doberman Pinscher and Boxer breeds present a higher prevalence of infection, and the relationship between antibodies’ serum titer and staging of disease was confirmed. Differences between age and sex were not found.Leishmaniosis is an important zoonotic protozoan disease primarily spread to the Mediterranean region by Leishmania infantum, the predominant protozoan species, which accounts for the majority of cases. Development of disease depends on the immune response of the definitive host and, predictably, their genetic background. Recent studies have revealed breed-typical haplotypes that are susceptible to the spread of the protozoan parasite. The objective of this study was to analyze the prevalence of leishmaniosis on a Mediterranean island and determine the relationship between disease prevalence and breed. In addition, information on seropositive animals was recorded to characterize animals affected by the disease. To study the prevalence, a total of 3141 dogs were analyzed. Of these, the 149 infected animals were examined for age, sex, antibody titer, and disease stage. We observed a prevalence of 4.74%, which varied between breeds (p < 0.05). The Doberman Pinscher and Boxer breeds had the highest prevalence of leishmaniosis. Significant differences were observed between breeds with common ancestors, emphasizing the important genetic component. Finally, regarding the characterization of seropositive animals, the distribution is similar to other studies. We discovered a relationship (p < 0.05) between the number of antibody titers and the clinical disease stage, which was also present in Leishmania infantum, suggesting that the development of the disease depends on the humoral or Th2 immune response with ineffective antibodies.

Differential acute-phase protein responses in dogs seropositive or seronegative for Neospora caninum.

Neospora caninum is one of the most prevalent Apicomplexa parasites that causes abortion in cattle, as it infects dogs as its definitive host, causing subclinical disease or active neosporosis, marked by meningoencephalitis, and myopathies with muscle and neuromuscular signs of disease. This study aimed to evaluate the acute phase protein response in dogs seropositive and seronegative for N. caninum. Serum samples of 72 dogs were tested by an immunofluorescence antibody test using N. caninum NC-1 strain, and the study population was divided into four groups: symptomatic - muscular and/or neuromuscular signs - and seropositive (n = 16); symptomatic and seronegative (n = 9); asymptomatic and seropositive (n = 34); and asymptomatic and seronegative (n = 13). C-reactive protein (CRP) was measured via immunoturbidimetric assay and serum haptoglobin (Hp) via hemoglobin-binding capacity assay. In the symptomatic groups, seropositive dogs had higher levels of Hp, but not CRP, while seronegative dogs had higher CRP levels. There was no difference in CRP concentration in asymptomatic dogs. Dogs with neuromuscular signs had higher concentrations for Hp in the group seropositive. Hp concentration did not differ between dogs seropositive and seronegative dogs for each group. Serum Hp and CRP could not sufficiently alone flag subclinical infections. Measurement of CRP and Hp concentrations could be clinically valuable to the diagnosis of neurological diseases, and their relative change may indicate the stage of the infection, although their sole use is not able to support the diagnosis of canine neosporosis. Further studies are encouraged to evaluate the specific dynamics of acute phase proteins in canine neosporosis. Serum samples of 72 dogs were tested by an immunofluorescence antibody test using N. caninum NC-1 strain, and the study population was divided into four groups: (1) dogs with muscular and/or neuromuscular signs and seropositive for N. caninum; (2) dogs with muscular and/or neuromuscular signs and seronegative for N. caninum; (3) dogs seropositive for N. caninum with no neuromuscular signs; and (4) healthy dogs and seronegative for N. caninum. The study evaluated if N. caninum infection could have pathophysiological changes activating the acute phase response and an increase in the concentration of acute phase proteins in serum.

Preoperative Oral Administration of Yunnan Baiyao and Its Effect on Coagulation Parameters in Tick-Borne Disease and/or Heartworm Seropositive Dogs: A Pilot Study

The overall goal of this clinically focused pilot study was to investigate the preoperative benefit of oral administration of Yunnan Baiyao (YB) to Ehrlichia. canis, Anaplasma platys and/or heartworm seropositive canines. A total of 12 clinically normal dogs undergoing sterilization procedures were randomly subdivided into Control/Placebo Group (n=6) or Treatment Group (n=6). Each patient received three oral doses of YB (0.5g/5kg) or placebo every twelve hours with the last dose given the evening before surgery. Citrated blood measurements for prothrombin time (PT), activated partial thromboplastin time (aPTT), and fibrinogen were obtained before the first YB dose and after the third dose. Intraoperative blood loss was estimated by blood-soaked gauze sponge counts. The study found the Control Group’s mean aPTT increased by 3.8% while the Treatment Group’s decreased by 0.42%. PT values were slightly decreased in both groups. Fibrinogen decreased in controls (9.7%) but had a modest increase in treated dogs (12.4%). Intraoperative blood loss was increased in controls (3%) compared to the Treatment Group (mean±SD: 6.6±6.8 vs. 6.4±3.6, respectively). Findings from the study which suggest preoperative benefits from YB administration to seropositive dogs include stabilizing aPTT and fibrinogen values along with reduced intraoperative blood loss in YB treated dogs. Although these modest findings were not statistically significant in this small study, the biological trends suggest potential benefits of preoperative administration of YB before routine elective surgeries in seropositive patients and support a clinical trial with larger sample size.

The Emergence of SARS-CoV-2 within the Dog Population in Croatia: Host Factors and Clinical Outcome.

Over a year into the COVID-19 pandemic, there is growing evidence that SARS-CoV-2 infections among dogs are more common than previously thought. In this study, the prevalence of SARS-CoV-2 antibodies was investigated in two dog populations. The first group was comprised of 1069 dogs admitted to the Veterinary Teaching Hospital for any given reason. The second group included dogs that shared households with confirmed COVID-19 cases in humans. This study group numbered 78 dogs. In COVID-19 infected households, 43.9% tested ELISA positive, and neutralising antibodies were detected in 25.64% of dogs. Those data are comparable with the secondary attack rate in the human population. With 14.69% of dogs in the general population testing ELISA positive, there was a surge of SARS-CoV-2 infections within the dog population amid the second wave of the pandemic. Noticeably seroprevalence of SARS-CoV-2 in the dog and the human population did not differ at the end of the study period. Male sex, breed and age were identified as significant risk factors. This study gives strong evidence that while acute dog infections are mostly asymptomatic, they can pose a significant risk to dog health. Due to the retrospective nature of this study, samples for viral isolation and PCR were unavailable. Still, seropositive dogs had a 1.97 times greater risk for developing central nervous symptoms.

Seroprevalence of Brucella canis in canines from a dog shelter in Bogotá, Colombia

ResumenIntroducción. El riesgo de infección con Brucella canis en humanos y perros aumenta con la exposición constante a perros portadores asintomáticos. En Colombia hay evidencia de infección con B. canis en personas que conviven con perros. Una preocupación adicional en Bogotá es la falta de información actualizada sobre la prevalencia de la infección en perros destinados a programas de adopción.Objetivo. Establecer la seroprevalencia de la infección por B. canis en perros de un refugio para animales de compañía destinados a la adopción en Bogotá.Materiales y métodos. Se hizo un estudio descriptivo de corte transversal en un refugio para animales de Bogotá. Se detectaron anticuerpos contra B. canis en el suero de 51 perros (28 hembras y 23 machos) mediante una prueba inmunocromatográfica de flujo lateral. Asimismo, los individuos positivos se analizaron con PCR para la detección del ADN de Brucella spp.Resultado. La seroprevalencia de B. canis fue del 1,96 % (1/51). El perro seropositivo correspondió a una hembra asintomática de tres años de edad en la cual no se detectó ADN bacteriano en sangre mediante la PCR.Conclusiones. La seroprevalencia representada por un solo perro con IgG anti-B. canis puede considerarse un riesgo potencial para las poblaciones de perros y humanos, ya que podría tratarse de un animal con infección persistente capaz de diseminar la bacteria.

Field assessment of dog as sentinel animal for plague in endemic foci of Madagascar.

The epidemiology of Yersinia pestis, the causative agent of plague, involves vectors and reservoirs in its transmission cycle. The passive plague surveillance in Madagascar targets mainly rodent and fleas. However, carnivores are routinely surveyed as sentinels of local plague activity in some countries. The aim of this study is to assess the use of domestic dog (Canis familiaris) as sentinel animal for field surveillance of plague in a highly endemic area in Madagascar. Cross-sectional surveys of plague antibody prevalence in C. familiaris were conducted in endemic areas with contrasting histories of plague cases in humans, as well as a plague free area. Rodent capture was done in parallel to evaluate evidence for Y. pestis circulation in the primary reservoirs. In 2 sites, dogs were later re-sampled to examine evidence of seroconversion and antibody persistence. Biological samplings were performed between March 2008 and February 2009. Plague antibody detection was assessed using anti-F1 ELISA. Our study showed a significant difference in dog prevalence rates between plague-endemic and plague-free areas, with no seropositive dogs detected in the plague free area. No correlation was found between rodents and dog prevalence rates, with an absence of seropositive rodents in some area where plague circulation was indicated by seropositive dogs. This is consistent with high mortality rates in rodents following infection. Re-sampling dogs identified individuals seropositive on both occasions, indicating high rates of re-exposure and/or persistence of plague antibodies for at least 9 months. Seroconversion or seropositive juvenile dogs indicated recent local plague circulation. In Madagascar, dog surveillance for plague antibody could be useful to identify plague circulation in new areas or quiescent areas within endemic zones. Within active endemic areas, monitoring of dog populations for seroconversion (negative to positive) or seropositive juvenile dogs could be useful for identifying areas at greatest risk of human outbreaks.

Existence of Similar Leptospira Serovars among Dog Keepers and Their Respective Dogs in Mwanza, Tanzania, the Need for a One Health Approach to Control Measures.

This study investigated seroepidemiology of Leptospira serovars among the dog keepers and their dogs in the city of Mwanza, Tanzania. A total of 205 dog keepers and 414 dogs were tested for Leptospira antibodies using a microscopic agglutination test (MAT). The median age of the dog keepers was 26 (inter quartile range (IQR): 17–40) years and median duration of keeping dogs was 36 (IQR: 24–120) months. The seropositivity of Leptospira antibodies was (33/205 (16.1%, 95% CI: 11.0–21.1) among dog keepers and (66/414 (15.9%, 95% CI: 12.4–19.4) among dogs, p = 0.4745. Among the serovars tested (Sokoine, Grippotyphosa, Kenya, Pomona and Hebdomadis), the most prevalent serovar was Sokoine in both dog keepers and their dogs (93.9% (31/33) vs. and 65.1% (43/66), p = 0.009). Thirty-one out of thirty-three seropositive dog keepers (93.9%) had dogs positive for Leptospira antibodies with 28 (84.9%) having similar serovars with their respective seropositive dogs. Having tertiary education (AOR: 0.24, 95% CI: 0.07–0.84, p = 0.026) independently protected individuals from being Leptospira seropositive. More than three quarters of dog keepers had similar serovars as their dogs, necessitating one health approach to control measures in endemic areas.

A serological survey of severe acute respiratory syndrome coronavirus 2 in dogs in Wuhan.

The novel coronavirus disease (COVID‐19) caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) has resulted in an unprecedented public health crisis and economic losses. Although several cases of cats and dogs infected with SARS‐CoV‐2 have been reported during this outbreak, the prevalence of SARS‐CoV‐2 in dog and its transmission among other companion animals are still unknown. Here, we report an extensive serological study of SARS‐CoV‐2 infection in dogs in Wuhan and analyse the infection rates at different stages of the pandemic outbreak. A total of 946 dogs serum samples were collected from Wuhan, of which 36 samples were obtained prior to the pandemic outbreak. Indirect enzyme‐linked immunosorbent assay (ELISA) showed that 16 sera collected during the outbreak were detected as positive through the receptor‐binding domain (RBD) of SARS‐CoV‐2. Of these 16 sera, 10 exhibited measurable SARS‐CoV‐2‐specific neutralizing antibodies whose titres ranged from 1/20 to 1/180. No serological cross‐reactivity was detected between SARS‐CoV‐2 and canine coronavirus (CCV). Furthermore, with the effective control of the outbreak, a decrease in the SARS‐CoV‐2 seropositive dog number was observed. Our results suggest that SARS‐CoV‐2 has infected companion dogs during the outbreak, and that COVID‐19 patient families have a higher risk of dog infection. Our findings deepen our understanding of the infection of SARS‐CoV‐2 in dogs and provide an important reference for prevention of COVID‐19.

Molecular and serological evaluation of zoonotic visceral leishmaniasis in dogs in a rural area of Fars province, southern Iran, as a source of Leishmania infantum infection.

Canine visceral leishmaniasis (CVL) is endemic in the southern parts of Iran. The current study aimed at molecular and serological evaluation of zoonotic visceral leishmaniasis in dogs in Fars province, southern Iran. Blood samples were collected from 60 dogs in the three villages in Fars Province. Serum samples were tested for antibodies against L. infantum by direct agglutination test (DAT). DNA was extracted from each dog's buffy coat and tested by PCR, targeting the Leishmania ITS‐2 region. From a total of 60 studied dogs, 25 (41.7%) were female, and 35 (58.3%) were male. Dogs' age ranged from 1 to 7 years, with a mean age of 2.97 (±1.4) years. Anti‐Leishmania antibodies were detected in sera samples of 28 (46.7%) dogs, (titre ≥ 1:320). Out of 28 seropositive cases, 13 (46.4%) were female, and 15 (53.6%) were male. Association between seropositivity and dogs’ clinical signs was statistically significant (p < .05). Leishmania DNA was detected in the buffy coat of 3 of 60 studied dogs which were all seropositive by DAT. The PCR products were sequenced and molecular analysis showed that two of the isolates were Leishmania infantum, and one was L. tropica. The high proportion of seropositive dogs indicates the important role of these animals in the epidemiology of the disease in the region. Infected dogs with or without signs, especially those that are molecularly positive, can act as an active reservoir of the disease in the area.

Socio-economic and environmental factors associated with the occurrence of canine infection by Leishmania infantum in Teresina, Brazil.

American visceral leishmaniasis (AVL) is a zoonosis caused by protozoan parasites of the genus Leishmania. In Brazil, the disease is caused by Leishmania infantum and the main vector is the phlebotomine sandfly Lutzomyia longipalpis, found both in natural ecotopes and in the rural and urban environments, being very well adapted to the peridomestic environment. The domestic dog has been incriminated as the main reservoir of the parasite in the urban environment, but the control measures based on culling seropositive dogs have not shown to be effective to contain the spread of the disease throughout the country. Many studies evaluated risk factors for human visceral leishmaniasis but few focused on the socioeconomic and environmental factors associated with infection among dogs. Knowledge of these factors might help identify the conditions that contribute to the maintenance of transmission cycles in the urban environment and identify new targets for intervention. The objective of this study was to assess the association between socioeconomic and environmental factors and the occurrence of canine leishmaniasis at Teresina city, Brazil. This cross-sectional study was developed in ten districts of Teresina, involving 532 houses and 810 dogs. Peripheral blood samples were collected by vein punction using vacutainer tubes without anticoagulant for performing serological test (indirect immunofluorescence - IFI). Serum samples with IFI titers ≥1: 80 were considered positive. Owners of the selected dwellings were interviewed using a semi-structured questionnaire addressing socioeconomic and environment aspects. The association between variables and seropositivity was assessed through multilevel logistic regression models. Global seropositivity was 39%. There was no statistically significant difference between seropositivity and age and sex of animals, literacy of the household head, presence of other domestic animals or with household characteristic like water supply, inadequate sewage disposal system, type of floor and roof. Mixed-breed dogs and those living for a long time in houses with absence of masonry walls and presence of a kennel showed higher odds of seropositivity. These results suggest that some peridomestic characteristics, especially the absence of barriers that allow dogs to have free access to the street, in association with the presence of a kennel, might contribute to maintaining the infection cycle in urban areas. Intervention measures oriented to the management of the peridomestic environment and responsible dog possession could be useful tools for reducing disease burden in endemic area.

Dogs as Sentinels for Flavivirus Exposure in Urban, Peri-Urban and Rural Hanoi, Vietnam.

Diseases caused by flaviviruses, including dengue fever and Japanese encephalitis, are major health problems in Vietnam. This cross-sectional study explored the feasibility of domestic dogs as sentinels to better understand risks of mosquito-borne diseases in Hanoi city. A total of 475 dogs serum samples from 221 households in six districts of Hanoi were analyzed by a competitive enzyme-linked immunosorbent assay (cELISA) for antibodies to the pr-E protein of West Nile virus and other flaviviruses due to cross-reactivity. The overall flavivirus seroprevalence in the dog population was 70.7% (95% CI = 66.4–74.8%). At the animal level, significant associations between seropositive dogs and district location, age, breed and keeping practice were determined. At the household level, the major risk factors were rural and peri-urban locations, presence of pigs, coil burning and households without mosquito-borne disease experience (p < 0.05). Mosquito control by using larvicides or electric traps could lower seropositivity, but other measures did not contribute to significant risk mitigation of flavivirus exposure in dogs. These results will support better control of mosquito-borne diseases in Hanoi, and they indicate that dogs can be used as sentinels for flavivirus exposure.

A Novel Sampling Model to Study the Epidemiology of Canine Leishmaniasis in an Urban Environment.

Background: Visceral leishmaniasis (VL) is one of the most important parasitic diseases in the world. The domestic dog is the main reservoir of zoonotic VL and a high prevalence of canine leishmaniasis (CanL) is associated with transmission of infection to humans. Here we describe the methodology used to obtain a rapid and representative sample of domestic dogs in the city of Posadas, Misiones, and compare the prevalence of Leishmania infection with a sample of shelter dogs.Methodology: We used the city land registry to make a random selection of homes and systematically recruited 349 domestic dogs from the selected properties. We also included all dogs from the main canine shelter within the city. Dogs were examined by two experienced veterinarians who recorded the presence of clinical signs common in CanL using a standardized protocol. We extracted a blood sample from each dog and performed four different serological tests to reveal the presence of anti-Leishmania antibodies.Results: After clinical examination, 145 domestic dogs (41.5%) and 63 (90%) shelter dogs had clinical signs compatible with CanL (p < 0.001). The seroprevalence among domestic dogs was 20.1% (95% CI 16.1–24.6) which was significantly lower than among the abandoned dogs (38.6%, 95% CI 27.7–50.6, p < 0.001). The spatial distribution of infected dogs was fairly homogenous throughout the city. Among domestic dogs, we observed a positive association between where the dog slept and presence of anti-Leishmania antibodies (p = 0.034). Of the seropositive domestic dogs 38 (54.4%) were asymptomatic.Conclusions: Our findings demonstrate how seroprevalence results can be highly influenced by sampling methodology. We demonstrate how the land registry can be used to estimate the prevalence of CanL in representative sample of domestic dogs in an urban setting, allowing decision makers to deepen their understanding the epidemiology of CanL in a timely and efficient manner for the development of plans to address both human and canine disease.