EVALUATION OF PELIBUEY LAMBS BORN TO MOTHERS PHENOTYPICALLY SEGREGATED ACCORDING TO RESISTANCE TO GASTROINTESTINAL NEMATODES IN THE HUMID TROPICS OF MEXICO.

The objective was to evaluate the effect of the resistance of ewes to gastrointestinal nematodes (GIN) on the parasitologic and productive performance of their lambs during preweaning and postweaning periods. Offspring from 44 Pelibuey ewes classified as resistant or susceptible to GIN were evaluated. During the preweaning period, birth weight (BW), live weight (LW) at 35 and 70 days of age, and live weight changes (LWC) were determined in 73 lambs. During the postweaning period, 20 lambs to susceptible or resistant ewes were evaluated. The lambs were challenged under natural GIN infections and artificial infection with L3 of Haemonchus contortus. The fecal egg count (FEC), hematocrit (HT), peripheral eosinophil count, plasma protein, LW, and LWC were determined. There were no differences among parameters evaluated during preweaning (P > 0.05). The type of lambing (single or multiple) affected the BW, LW, and LWC (P < 0.01). The sex (male) of the lamb had a positive effect on BW at 35 and 70 days of age (P < 0.05). After weaning, lambs of susceptible ewes showed higher FEC than resistant ewes (P < 0.05). The HT of lambs to resistant ewes was higher than those the susceptible group (P < 0.01). In conclusion, offspring of resistant ewes show low FEC compared with those susceptible during the postweaning stage.

Relationships among body condition score, FAMACHA© score and haematological parameters in Pelibuey ewes.

The objective of the present study was to determine the associations between the FAMACHA© score, body condition score (BCS) and several haematological parameters of Pelibuey ewes. In total, 52 clinically healthy Pelibuey ewes were evaluated in this study. A blood sample was collected from each animal to determine haematological variables. The BCS was evaluated on a scale of 1 to 5 and subsequently grouped into four categories: (1) < 1.5, (2) 2.0-2.5, (3) 3.0-3.5 and (4) > 4.0. The coloration of conjunctival mucosa was evaluated using the FAMACHA© system. The analysed haematological parameters were red blood cell (RBC) count, haemoglobin (HGB), haematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), red blood cell distribution width standard deviation (RDW-SD) and red blood cell distribution width coefficient of variation (RDW-CV). A descriptive statistical analysis was performed, and the Pearson correlation coefficients between variables were estimated. Haematological parameters were analysed with one-way analyses of variance, and the Tukey test was applied when significant differences were detected. The FAMACHA© score was only associated with MCHC (r = - 0.30, P < 0.05). The haematological parameters of RBC count, HCT, RDW-SD and RDW-CV statistically differed among BCS groups. The BCS was associated with RBC count, HCT, RDW-SD and RDW-CV, with r values ranging from 0.35 to 0.48. The haematological values were similar to those reported in ewes from Iran and Iraq. Hence, the optimization of the BCS calculation of Pelibuey ewes can generate association tables with haematological parameters to aid in the sanitary and feeding management of sheep.

Ovarian dynamics of buffalo (Bubalus bubalis) synchronized with different hormonal protocols.

The study evaluates the effect of three hormonal protocols on ovarian dynamics and progesterone (P4) secretion of buffalo (Bubalus bubalis). Twenty-nine pluriparous Murrah buffaloes were used. The protocols were as follows: OVSYNCH (n = 10): 100 µg of gonadorelin (day 0), 500 µg of cloprostenol (day 7), and 100 µg of gonadorelin (day 9). CIDR+EB (intravaginal device (CIDR®) + estradiol benzoate; n = 10): CIDR plus 2 mg of EB (day 0), withdrew of CIDR, 500 µg of cloprostenol (day 7) and 1 mg of EB (day 8). CIDR+eCG (n = 9): CIDR plus 2 mg of EB (day 0), withdrew of CIDR, 500 µg of cloprostenol and 400 IU of eCG (day 7). Follicles were counted with an ultrasound and measured at 0, 24, and 54 h. The maximum follicle diameter and ovulation were evaluated at 70, 80, and 94 h after CIDR withdrew. Estrous was detected per 1 h three times daily. Blood samples were collected on days 0, 7, 10, 15, and 22 to determine P4 concentration. In CIDR+EB protocol, 50% of buffaloes presented estrous, at 69.6 h. All buffaloes ovulated. CIDR+eCG group had the shortest (69 h) ovulation time. No treatment differences for follicular population, maximum follicle diameter, and P4 concentration on days 7 and 10 (P > 0.05) were found. The P4 concentration in OVSYNCH and CIDR+eCG protocols were > 1 ng/ml, on days 15 and 22 (P < 0.05). There was no difference in ovarian activity; however, the P4 secretion was normal in the OVSYNCH and CIDR+eCG protocols compared to the CIDR+EB protocol.

Entomological and virological surveillance for dengue virus in churches in Merida, Mexico.

This study was designed to assess whether churches in endemic dengue districts in Merida, Mexico provide suitable breeding habitats for mosquitoes and are potential sites for dengue virus (DENV) transmission. Churches were inspected for immature and adult mosquitoes once every week from November 2015 to October 2016. A total of 10,997 immatures of five species were collected. The most abundant species were Aedes aegypti (6,051) and Culex quinquefasciatus (3,018). The most common source of immature Ae. aegypti were buckets followed by disposable containers. Adult collections yielded 21,226 mosquitoes of nine species. The most common species were Cx. quinquefasciatus (15,215) and Ae. aegypti (3,902). Aedes aegypti were found all year long. Female Ae. aegypti (1,380) were sorted into pools (166) and assayed for flavivirus RNA by RT-PCR and Sanger sequencing. Two pools were positive for DENV (DENV-1 and 2). In conclusion, we demonstrated that some churches in Merida are infested with mosquitoes all year long and they potentially serve as sites for DENV transmission and should therefore be considered for inclusion in mosquito and arboviruses control and surveillance efforts.

Study of Aedes aegypti population with emphasis on the gonotrophic cycle length and identification of arboviruses: implications for vector management in cemeteries.

Aedes aegypti is the vector of the arboviruses causing dengue, chikungunya and zika infections in Mexico. However, its presence in public places has not been fully evaluated. In a cemetery from Merida, Yucatan, Mexico, the productivity of Ae. aegypti, the gonotrophic cycle, and the presence of Ae. aegypti females infected with arboviruses were evaluated. Immature and adult mosquitoes were inspected every two months between April 2016 to June 2017. For the gonotrophic cycle length, the daily pattern of total and parous female ratio was registered and was analyzed using time series analysis. Ae. aegypti females were sorted into pools and assayed for flavivirus RNA by RT-PCR and Sanger sequencing. Aedes aegypti immatures represented 82.86% (8,627/10,411) of the collection. In total, 1,648 Ae. aegypti females were sorted into 166 pools. Two pools were positive; one for dengue virus (DENV-1) and the other for zika virus (ZIKV). The phylogenetic analysis revealed that the DENV-1 is more closely related to isolates from Brazil. While ZIKV is more closely related to the Asian lineage, which were isolates from Guatemala and Mexico. We report some evidence of vertical transmission of DENV-1 in nulliparous females of Ae. aegypti. The gonotrophic cycle was four and three days in the rainy and dry season, respectively. The cemetery of Merida is an important focus of Ae. aegypti proliferation, and these environments may play a role in arboviruses transmission; probably limiting the efficacy of attempts to suppress the presence of mosquitoes in domestic environments.

Study of gastrointestinal parasites in water buffalo (Bubalus bubalis) reared under Mexican humid tropical conditions.

The objective was to determine the frequency of gastrointestinal parasites (GP) genera affecting water buffalo (Bubalus bubalis) reared under humid tropical conditions of Mexico. Three hundred eighty-three Munrah breed water buffalo were included, 251 adult females and 132 calves. Feces were directly collected form the rectum of the animals and processed by the McMaster technique. Coprocultures were made to identify the genera of the nematodes. The frequency of GP in B. bubalis was 42%, independently of their age, 60% of calves resulted parasitized. Age had a strong association with the presence of GP (Xi2 = 77.4014, d.f. = 1, p = 0.001). The family Trichostrongylidae was found in both age groups. The genera identified were Strongyloides sp. (47.2%), Cooperia sp. (33.9%), and Haemonchus sp. (10.4%), as well as Eimeria sp., Moniezia sp., Trichuris sp., and Strongyloides sp. The highest parasite burden corresponded to the genus Strongyloides sp. with 1108.9 EPG. There is a need to carry out further studies in order to know the prevalence and incidence of nematode affecting to B. bubalis as an introduced animal species to Mexican tropics.

Prevalence of gastrointestinal parasites in domestic dogs in Tabasco, southeastern Mexico.

The overall goal of this study was to estimate the prevalence of gastrointestinal (GI) parasites in dogs in the city of Villahermosa in Tabasco, Mexico. The study population consisted of 302 owned dogs that had limited access to public areas. A fecal sample was collected from each animal and examined for GI parasites by conventional macroscopic analysis and centrifugal flotation. Fecal samples from 80 (26.5%) dogs contained GI parasites. Of these, 58 (19.2%) were positive for helminths and 22 (7.3%) were positive for protozoan parasites. At least seven parasitic species were identified. The most common parasite was Ancylostoma caninum which was detected in 48 (15.9%) dogs. Other parasites detected on multiple occasions were Cystoisospora spp. (n = 19), Toxocara canis (n = 7) and Giardia spp. (n = 3). Three additional parasites, Dipylidium caninum, Trichuris vulpis and Uncinaria spp., were each detected in a single dog. No mixed parasitic infections were identified. In summary, we report a moderately high prevalence of GI parasites in owned dogs in Villahermosa, Tabasco. Several parasitic species identified in this study are recognized zoonotic pathogens which illustrates the important need to routinely monitor and treat dogs that live in close proximity to humans for parasitic infections.

Prevalence of gastrointestinal parasites in domestic dogs in Tabasco, southeastern Mexico / Prevalência de parasitas gastrointestinais em cães domésticos em Tabasco, sudeste do México

Abstract The overall goal of this study was to estimate the prevalence of gastrointestinal (GI) parasites in dogs in the city of Villahermosa in Tabasco, Mexico. The study population consisted of 302 owned dogs that had limited access to public areas. A fecal sample was collected from each animal and examined for GI parasites by conventional macroscopic analysis and centrifugal flotation. Fecal samples from 80 (26.5%) dogs contained GI parasites. Of these, 58 (19.2%) were positive for helminths and 22 (7.3%) were positive for protozoan parasites. At least seven parasitic species were identified. The most common parasite was Ancylostoma caninum which was detected in 48 (15.9%) dogs. Other parasites detected on multiple occasions were Cystoisospora spp. (n = 19), Toxocara canis (n = 7) and Giardia spp. (n = 3). Three additional parasites, Dipylidium caninum, Trichuris vulpis and Uncinaria spp., were each detected in a single dog. No mixed parasitic infections were identified. In summary, we report a moderately high prevalence of GI parasites in owned dogs in Villahermosa, Tabasco. Several parasitic species identified in this study are recognized zoonotic pathogens which illustrates the important need to routinely monitor and treat dogs that live in close proximity to humans for parasitic infections.

Resumo O objetivo geral deste estudo foi estimar a prevalência de parasitas gastrointestinais (GI) em cães na cidade de Vilhahermosa, em Tabasco, México. A população estudada consistiu de 302 cães com donos, com acesso limitado a áreas públicas. Uma amostra fecal de cada animal foi coletada e examinada para parasitas GI por análise macroscópica convencional e centrífugo-flutuação. Amostras fecais de 80 (26,5%) cães apresentaram parasitas GI. Destes, 58 (19,2%) foram positivos para helmintos e 22 (7,3%) foram positivos para protozoários. Pelo menos 7 espécies parasitas foram identificadas. O parasita mais comum foi Ancylostoma caninum, detectado em 48 (15,9%) cães. Outros parasitas detectados em diversas ocasiões foram Cystoisospora spp. (n = 19), Toxocara canis (n = 7) e Giardia spp. (n=3). Adicionalmente, três parasitas foram detectados em apenas um cão – Dipylidium caninum, Trichuris vulpis e Uncinaria spp. Nenhuma infecção mista foi observada. Em resumo, nós identificamos neste trabalho uma prevalência moderadamente alta de parasitas GI em cães com donos, em Villahermosa, Tabasco. Várias espécies de parasitas identificados são reconhecidamente patógenos zoonóticos, o que indica a necessidade de monitorar rotineiramente e tratar infecções parasitárias em cães que vivem em proximidade a populações humanas.