Análisis exploratorio de enfermedades Rickettsiales transmitidas por garrapatas en perros de Ciudad Juárez, Chihuahua, México

During the last decade in northern Mexico, the interest in the study of zoonotic diseases such as anaplasmosis and canine ehrlichiosis, which are transmitted by ticks to both dogs and humans, has increased.The objective of this research was to evaluate the presence of Ehrlichia spp. and A. phagocytophilum in dogs and ticks from Ciudad Juarez, Chihuahua. The Polymerase Chain Reaction (PCR) technique determined a prevalence of 40% and 66% for Ehrlichia spp. and 27% and 13% for A. phagocytophilum in blood samples taken from dogs and in pools of Rhipicephalus sanguineus respectively. There was co-infection of both pathogens in 23% of the dogs and in 11% of the tick pools. The maximum value of the infection rate was 267.10, considering both pathogens. Rh. sanguineus was classified as a temperate lineage according to the sequencing analysis. The results suggest that there is a widespread infestation of Rh. sanguineus in the dog’s population. The pathogens associated with this tick species are circulating with a prevalence that goes from moderate to high, putting inhabitants of this border city at potential risk

Serologic evidence of rickettsial diseases associated with tick bites in workers of urban veterinary clinics

Background & objectives: Rickettsial and other zoonotic diseases are a latent risk for workers of veterinary clinics. The objective of this study was to evaluate the prevalence and the associated risk factors of parasitosis caused by Rhipicephalus sanguineus, and to estimate the seroprevalence of rickettsial diseases in workers of urban veterinary clinics of Juárez city, México. Methods: The participants of the study were recruited from 63 private veterinary clinics and hospitals. The serological analysis of the blood samples collected was carried out using immunofluorescence assay (IFA). The statistical analysis for prevalences, risk factors, and correlation was performed with the SAS program. Results: In total, 167 veterinary workers were included in the study. The prevalence of tick bites was 40% (67/167), and the risk factors associated with the occurrence of bites included the activities performed in the clinic and the number of labour hours spent per week. About 21% (35/167) of participants were seropositive to R. rickettsii, 28% (47/167) to Ehrlichia chaffeensis, and 24% (40/167) to Anaplasma phagocytophilum. A correlation was observed between: the number of workers in the clinics and the proportion of tick bites (r2 = 0.865); the prevalence of bites and the seropositivity of the participants to at least one pathogen (r2 = 0.924); and the number of bites per individual and infection to pathogens (r2 = 0.838). Interpretation & conclusion: Workers in urban veterinary clinics are highly exposed to tick bites and, therefore, to the diseases they transmit. Hence, it is important to implement prevention measures and perform constant monitoring of these diseases

Occupational risk for personnel working in veterinary clinics through exposure to vectors of rickettsial pathogens

Workers at veterinary clinics are exposed to zoonotic pathogens, which, though infrequently, can lead to serious consequences. The aim of the present study was to estimate the seroprevalence for rickettsial pathogens in veterinary clinic personnel in Ciudad Juárez, Chihuahua, Mexico. Voluntary participants included 106 veterinarians, 19 pet groomers, 36 veterinary assistants and 6 administrative workers who supplied blood samples taken by venipuncture. Detection of Rickettsia rickettsii, Ehrlichia spp. and Anaplasma phagocytophilum was conducted by indirect immunofluorescence assay (IFA) and polymerase chain reaction (PCR) techniques. To determine risk factors for the seroprevalence, the study considered social, demographic and occupational variables as well as the clinical signs and symptoms of the participants. Logistic regression procedures were performed, and the odds ratio (OR) was calculated with confidence intervals corresponding to a probability of 95%. The results indicate that 54% of the participants had a positive seroreaction to at least one of the pathogens evaluated and 2% were positive to all. The coexposure was as follows: 3% to R. rickettsii and A. phagocytophilum, 9% to Ehrlichia spp. and A. phagocytophilum, and 2% to Ehrlichia spp. and R. rickettsii. It was established that grooming posed the highest risk for R. rickettsii exposure. The implementation of appropriate management practices for zoonotic diseases is recommended to avoid health problems that may be life threatening to personnel in veterinary clinics

Host selection of Aedes aegypti and Culex quinquefasciatus females in a semi-desert environment in Northern Mexico

Transmission of arboviral diseases such as those caused by dengue, chikungunya and West Nile viruses involves hematophagous insects. Arbovirus transmission is a complex process in which host selection plays an important role that determines the contact rates between vulnerable hosts and infective vectors. This paper describes host selection of Aedes aegypti (Linnaeus) (Diptera: Culicidae) and Culex quinquefasciatus in suburban neighborhood houses located in the semi-desert environment of northern Mexico. All bloodmeal analyses were completed in engorged females collected by means of BG-GAT (BIOGENTS ®) traps and blood identification was made through PCR analysis using cytochrome b as reference gene. The results show that Ae. aegypti is feeding primarily on birds from the Galliformes and Columbiformes orders. On the other hand, Culex quinquefasciatus exhibits the same behavior as Ae. aegypti, selecting Galliformes as the main blood source group but exhibits different behavior regarding humans, feeding preferentially on humans over non-human mammals. Regarding resource utilization, Ae. aegypti had a broader niche (0.79) than Cx. quinquefasciatus(0.46). Pianka´s niche overlap index (0.79) showed that both species share many common hosts. Host selection for the mosquito species analyzed were found to be atypical from what is reported in the literature, which could have an impact on the vectorial capacity of the mosquitoes within the study are

Molecular identifcation and morphological variations of Dermacentor albipictus collected from two deer species in northern Mexico

In total, 57 ticks were collected from six white-tailed deer (Odocoileus virginianus) and three mule deer (O. hemionus) in northern Mexico during the 2017, 2018 and 2019 hunting seasons. Morphological features of adult male and female ticks were observed and photographed using a stereo-microscope and scanning electron micrography. The ticks were identifed as Dermacentor albipictus based on taxonomic keys. Molecular analysis using DNA amplifcation of the 16S rDNA and cytochrome oxidase 1 (COI) genes was employed to resolve the phylogenetic relationships from 18 strains of Dermacentor species. Bayesian phylogenetic analysis was performed in order to obtain a phylogenetic tree based on the concatenated sequence in the D. albipictus clade. The geometric morphometric analysis compared the body shape of ticks collected from specimens of two deer species by analyzing nine dorsal and ventral landmarks from both males and females. The results suggest that body shape variation in dorsal structures might be related to the host

First report of Siphonaptera parasites in Canis latrans in the Flora and Fauna Protection Area, Médanos de Samalayuca Chihuahua, Mexico

Siphonaptera are hematophage parasite vectors of both human and animal diseases. We aimed to identify ectoparasites parasitizing a coyote population (Canis latrans) in the northwest region of the Flora and Fauna Protection Area Médanos de Samalayuca, Chihuahua, Mexico. We captured 21 coyotes (15 males and 6 females) during the summer and winter of 2018. The individuals were anesthetized and thoroughly examined for ectoparasites. We found that 43% of the coyotes were infested. Based on characteristics such as the absence of pronotal and genal combs in the head, we identified 15 specimens as Pulex irritans. This is the first report of P. irritans in coyotes in Médanos de Samalayuca Chihuahua, Mexico

Analysis of bovine tuberculosis transmission in Jalisco, Mexico through whole-genome sequencing

Bovine tuberculosis, caused by M. bovis, is endemic in Mexico and has had a big impact on public health. Jalisco is considered to be an important dairy region in the country, accounting for approximately 19% of the total milk production. Within Jalisco, the region of Altos Sur holds the largest proportion of the cattle inventory of the state

Corpora lutea affect in vitro maturation of bovine cumulus-oocyte complexes and embryonic development after fertilization with sex-sorted or conventional semen

Influence of both the presence of a corpus luteum on the ovary and semen sex-sorting on development following in vitro fertilization is not yet conclusive. To determine the effect of these factors, 376 bovine oocytes were processed in vitro according to luteal presence on the ovary (CL+ and CL-) and type of semen used (sexed or conventional). Maturation rate was higher (P<0.01) in CL- (136/138; 98.6%), than in CL+ (217/238; 91.2%). Cleavage rate was lower (P<0.01) in CL+ with sexed semen (60/172; 34.9%) than in CL- with sexed semen (42/71; 59.1%) CL+ with conventional semen (47/66; 71.2%) and CL- with conventional semen (54/67; 85.1%). Compaction was similar (P=0.69) in CL- (49/99; 49.4%) and CL+ (50/107; 46.7%). Blastulation rate was higher (P<0.01) in CL- (26/99, 26.2%) than in CL+ group (13/107; 12.1%). Expansion rate was higher (P=0.01) in CL- (22/99; 22%) than in CL+ (11/107; 10.2%). Compaction rates were similar (P=0.78) in sex-sorted (50/102; 49.0%) or conventional semen (49/104; 47.1%) groups. Blastulation was also similar (P=0.91) with sex-sorted semen (19/102; 18.6%) and conventional semen (20/104; 19.2%). Rate of expanded blastocysts was similar (P=0.89) in sex-sorted (16/102; 15.6%) and conventional (17/104; 16.3%) semen groups. In conclusion, presence of CL can compromise maturation of the oocytes and their development, as a higher proportion of cleavage-stage embryos can be obtained with non-sexed semen with oocytes from ovaries without a CL

Effect of Moringa oleifera seed extract on antioxidant activity and sperm characteristics in cryopreserved ram semen

Semen cryopreservation damages sperm due to oxidative stress. This study evaluated the antioxidant capacity of Moringa oleifera seed extract in cryopreserved ram semen and the impact of the extract on sperm characteristics. Semen from eight hair rams (four rams per sampling) was allocated into four groups, according to their treatment prior to cryopreservation: Control (no extract), 0.5 (M0.5), 5.0 (M5.0), and 10.0 (M10) mg/mL of M. oleifera extract. The antioxidant activity (ferric reducing antioxidant power, FRAP) and the spermatic characteristics (sperm viability; progressive motility; fast motility; slow motility; acrosome damage; membrane damage; and mitochondrial activity) were assessed post-thawing. Variables were evaluated with analysis of variance followed by Tukey test. While no significant differences were detected in acrosomal damage, mitochondrial activity, fast-, or slow motility, the antioxidant activity was higher (P < 0.05) in M0.5 and M5 treatments. Viability and progressive motility increased in the M0.5 group (P < 0.05), whereas sperm membrane damage was lower (P < 0.05) in the same treatment. In conclusion, supplementation of ram semen with M. oleifera seed extract enhances antioxidant activity, sperm membrane integrity, viability, and progressive motility after thawing. This suggests that M. oleifera extract could be used as an antioxidant to improve the outcome of semen cryopreservation

Risk factors associated with retained placenta in dairy cattle in northern Mexico

The objective was to determine the association between different risk factors for placental retention (PR) in northern Mexico. Records of 2 492 Holstein cows from a commercial dairy herd located in Ciudad Juárez, Chihuahua, Mexico were used. Variables were analyzed by the chi-square test (c2) test and odds ratios (OR) were calculated to determine the association of the risk factors with PR. The total incidence of PR was 10.15%. The risk factors associated with RP were twin birth and premature birth, followed by stillbirths and dystocia. The presence of RP did not increase the number of inseminations, but decreased the days in milk in affected cows (p < 0.05). In conclusion, the risk factors twin birth, premature birth, stillbirth, dystocia and age of the cow affect the incidence of RP, while the delivery season does not predispose to the presentation of this alteration