Epidemiology of Neospora caninum and Toxoplasma gondii infection in venison from Aguascalientes, Mexico.

The objective of the study was to estimate the seroprevalence of Neospora caninum and Toxoplasma gondii in venison from Aguascalientes, Mexico, their possible association with some risk factors, and to identify the presence of parasite DNA in blood and tissues. For this study, 5 farms and four species of venison were included, where 43 blood serum samples were obtained and in 37 of these animals a peripheral blood sample was also obtained; from hunted deer, 6 liver and 2 heart samples were obtained. The samples were analyzed by ELISA and PCR tests, respectively. The association between the serological status and the possible risk factors was estimated. The overall seroprevalence in N. caninum was 47% (20/43; CI 95% 31-62), with positive animals in all farms in a range of 18 to 100%, while for T. gondii it was 49% (21/43; CI 95% 33-64), with positive animals in 80% of farms in a range of 18 to 100%. The prevalence of N. caninum DNA detection in blood was 59% (22/37; CI 95% 42-74), with positive animals in all farms, in a range of 45 to 100%, while in T. gondii it was 76% (28/37; CI 95% 58-87), with positive animals in all farms, in a range of 56 to 100%. Age (> 4 years) was identified as associated with seroprevalence in N. caninum (OR 5.2) and in T. gondii (OR 12.7). DNA from both parasites was detected in the liver and heart samples. The results shown that venison populations included in the study are living in an environment highly contaminated with oocysts excreted by the definitive host.

EPIDEMIOLOGY OF TOXOPLASMA GONDII AND NEOSPORA CANINUM INFECTION IN GOATS FROM AGUASCALIENTES, MEXICO.

The objective of this study was to describe the epidemiology of Toxoplasma gondii and Neospora caninum infection by estimating seroprevalence and its association with certain risk factors in goats from Aguascalientes, Mexico. A total of 150 blood samples was taken from 10 farms and serum samples were subjected to enzyme-linked immunosorbent assay indirect test to detect T. gondii and N. caninum antibodies; the association between seroprevalence and some potential risk factors was estimated through logistic regression analysis. The general seroprevalence for T. gondii was 12.6%, observed in the farms in a range of 6.6 to 60%, finding seropositive animals in 80% of them; for N. caninum the seroprevalence was 3.3% and in farms a range of 6.6 to 13.3% was identified and 30% of them had at least 1 seropositive animal. The coinfection was 0.66%. The risk analysis for T. gondii identified a history of abortions (odds ratio 9.25) as a factor associated with seroprevalence; for N. caninum, no risk factor was identified.

Determination of the discriminant doses to identify resistance to fipronil, flumethrin and coumaphos, in Rhipicephalus sanguineus s.l. (Acari: Ixodidae) from Mexico.

Rhipicephalus sanguineus s.l. is an intra- and peridomiciliary tick of medical and veterinary importance, whose control is carried out through the application of various ixodicides, to which it can develop resistance. The objective of this work was to determine the discriminant doses (d.d.) to identify resistance against three ixodicides - fipronil, flumethrin and coumaphos - in R. sanguineus s.l. larvae originating from Mexico. Engorged ticks were collected from naturally infested dogs residing in rural communities in five Mexican states; the dogs had no history of recent treatment with ixodicides. All ticks were identified as R. sanguineus s.l. They were incubated for 25 days and their progeny was used in the larval package test (LPT) to be exposed to d.d. as determined in Rhipicephalus microplus, and those that were susceptible were analyzed using the LPT with six concentrations, for fipronil from 0.1 to 0.003125%, for flumethrin from 0.02 to 0.000625% and for coumaphos from 0.4 to 0.0125%. Mortality was analyzed with Probit methodology, to calculate the 50 and 99% lethal concentrations (LC50 and LC99). The d.d. was determined as a consensus value by multiplying the LC99 value × 2. Nine double susceptible samples (fipronil + flumethrin) and one triple susceptible sample (fipronil + flumethrin + coumaphos) were found; the d.d. determined were fipronil 0.05%, flumethrin 0.01% and coumaphos 0.43%. These doses can be used to rapidly and inexpensively identify resistant populations in samples collected in the field.

Seroprevalence of Toxoplasma gondii Infection and Associated Risk Factors in Different Populations of Dogs from Aguascalientes, Mexico.

CONTEXT AND PURPOSE: This work aimed to study the seroprevalence of natural infection by T. gondii in different population segments of dogs from Aguascalientes, Mexico as well as its possible association with some risk factors. METHODS: The study included 210 clinically healthy dogs from three population segments: rural, stray and pet. A blood serum sample was collected on a single occasion and processed by indirect immunofluorescence considering a dilution of 1:16 as a positive reaction; the association between the presence of antibodies and the potential risk factors was estimated with logistic regression. RESULTS: The overall prevalence of anti-T. gondii antibodies in the studied population was 59% (123/210; CI 95% 51-65) being different between population segments, in rural dogs 74% (59/80; CI 95% 62-82), in stray dogs 60% (48/80; CI 95% 48-70) and in pet dogs 32% (16/50; CI 95% 19-46), the titers of the positive sera were in a range of 1:16-1:128. In rural dogs the seroprevalence according to the municipality was in a range of 55% to 100% finding positive dogs in all the studied municipalities. The zootechnical function of guarding the property in rural dogs was identified as a risk factor (OR 2.4), while in pet dogs it was living with cats (OR 7) as well as sharing the drinking water container (OR 4); in stray dogs it was not possible to identify any risk factor. CONCLUSIONS: This study documents the wide presence of anti-T. gondii antibodies in the population groups examined, this being more important in rural dogs.

Determination of a Discriminant Dose to Identify Resistance to Amitraz in Rhipicephalus sanguineus s.l. (Acari: Ixodidae) from Mexico.

The brown dog tick, Rhipicephalus sanguineus s.l., is considered the most widely distributed three-host tick in the world and has medical and veterinary importance; the control of infestation is carried out with acaricides, towards which it can develop resistance. This study aimed to determine the discriminant dose (d.d) of amitraz to identify resistance in R. sanguineus s.l. larvae natives from Mexico and to evaluate its application in field-collected ticks. Engorged ticks were collected from naturally infested dogs residing in rural communities and were incubated for 25 days, and their progeny was used in a larval immersion test (LIT) to be exposed to the d.d. determined in Rhipicephalus microplus, and those that were susceptible were analyzed using the LIT in six concentrations. Mortality was analyzed through probit methodology to calculate the lethal concentration (LC) 50 and 99. The d.d. was determined as a consensus value by multiplying the LC99 × 2, and then, we proceeded to evaluate it in in-field samples by using the LIT technique. The d.d. calculated was 4 ppm. The in-field evaluation found 64% of the resistant samples to amitraz with mortality percentages between 98.3% and 0.35%. This dose can be used to rapidly and inexpensively identify resistant populations in samples collected in the field.

Presence of the toxigenic fungi Aspergillus spp. and Fusarium spp. in Musca domestica L. (Diptera: Muscidae) collected from dairy farms.

The objective of the study was to identify the presence of toxigenic fungi Aspergillus spp. and Fusarium spp. in domestic flies collected from dairy farms. We selected 10 dairy farms distributed in the central valley of the state of Aguascalientes, México. The flies were trapped using entomological traps with an olfactory attractant in 7 sites of the farm (silo-cutting surface, feed store, milking parlor, 3 feeders, and the rearing room). The fungi were cultivated in Sabouraud agar through direct sowing by serial dilutions to obtain the isolates, and a taxonomical identification was carried out under the microscope. The aflatoxins and zearalenone production capacity of the pure isolates were quantified using the ELISA test. The flies were present in all of the capture sites (45.3 flies, 567 mg, trap per day). We obtained 50 isolates of Aspergillus spp. genus, 12 of which produced aflatoxins (327 ± 143 µg/kg), whereas from 56 of the Fusarium spp. isolates, 10 produced large quantities of zearalenone (3,132 ± 665 µg/kg). These results suggest that the presence of domestic flies on dairy farms can constitute a source of dissemination for toxigenic fungi that can eventually contaminate grains and forage that are part of the daily cattle diet.

Seroepidemiology of Toxoplasma gondii infection and parasite DNA in free-range chickens in Aguascalientes, Mexico.

The objectives of the study were to estimate the prevalence of anti-Toxoplasma gondii antibodies in free-range chickens in Aguascalientes, Mexico, its association with certain risk factors, and the frequency of parasite DNA in the heart. Eighty-one small rural family farms were included, and blood and heart samples were taken from 150 clinically healthy, adult, free-range chickens. Serum samples were processed by indirect immunofluorescence antibody test considering a dilution of 1:16 as a positive reaction, while the DNA detection was done by PCR. The correlation between the presence of antibodies and the potential risk factors was estimated with logistic regression. The overall seroprevalence in the examined populations was 67%, with a range from 33% to 100% among municipalities, and 78% of the farms having at least one seropositive bird. The PCR test identified the presence of parasite DNA for one case only. Among the variables, the presence of cats and the presence of other animal species on the farm were the ones that had the highest values, while the presence of feral cats and the presence of noxious fauna were also identified as potential risk factors. The results indicate high soil contamination by T. gondii oocysts, which implies the active role of cats living on the farms.

Epidemiology of Neospora caninum infection in free-range chickens (Gallus gallus domesticus) in north central Mexico.

The objective of the present study was to investigate the epidemiology of natural infection by N. caninum in free-range chickens from Aguascalientes, Mexico, through identifying the presence of antibodies, its association with certain risk factors, and estimate the frequency of parasite DNA detection in the brain. The study included 150 clinically healthy chickens from 81 small family farms distributed throughout the state, from which blood and brain samples were taken. Serum samples were processed by indirect immunofluorescence considering a dilution of 1:50 as a positive reaction, while the DNA detection was done by PCR; the association between the presence of antibodies and the potential risk factors was estimated through logistic regression. The general anti-N. caninum presence of antibodies in the studied population was 46% (69/150, CI 95% 38-54), with titers of 1:50 in 38, 1:100 in 24, and 1:200 in 7, finding positive cases in 49% of the farms and in 91% of the municipalities that integrate the state. The presence of antibodies found in the municipalities was estimated in a range of 20 to 75%. The frequency of DNA detection was 6% (9/150, CI 95% 2-11). The grain supplementation was identified as the unique risk factor for infection (OR = 2.82; 95% CI, 1.18-6.73, p < 0.019).

Control of Haematobia irritans and Stomoxys calcitrans with Metarhizium anisopliae in naturally infested cattle / Control de Haematobia irritans y Stomoxys calcitrans con Metarhizium anisopliae en ganado naturalmente infestado

ABSTRACT Objective. Assess the efficacy of Metarhizium anisopliae strain 135 (Ma135) applied by aspersion to reduce simultaneous infestation of Haematobia irritans and Stomoxys calcitrans in naturally infested cattle maintained in a production system which combine grazing and confinement in pens. Materials and methods. Was applied an aqueous formulation of Ma135 (1x108 conidia/ml) on a nine cows group in six occasions with seven days interval, while the control group received the same formulation without conidial content. The infestation index was estimated daily for each fly independently; the effectiveness of the formulation was calculated using the Abbott's formula. Results. The Ma135 formulation had a reduction in the fly population of 58% for H. irritans and 69% for S. calcitrans, taking into consideration the six study weeks, in addition to causing no negative effects on animal health. An Infestation index reduction was observed from the first week post-treatment (p<0.05) and maintained this trend throughout the study. Conclusions. The present study has demonstrated the potential of strain Ma135 to reduce the simultaneous infestation of both hematophagous flies in cattle under conditions of natural infestation.

RESUMEN Objetivo. Evaluar la eficacia de la cepa 135 de Metarhizium anisopliae (Ma135) aplicada por aspersión para reducir la infestación simultánea de Haematobia irritans y Stomoxys calcitrans en ganado naturalmente infestado mantenido en un sistema de producción de leche que combina el pastoreo y el confinamiento en corrales. Materiales y métodos. Se aplicó una formulación acuosa de Ma135 (1x108 conidios/ml) a un grupo de nueve vacas en seis ocasiones con un intervalo de siete días, mientras que el grupo control recibió una solución compuesta por agua, Monooleato de polioxietileno sorbitán en solución 0.01% y un adyuvante agrícola al 0.1%. Se estimó diariamente el índice de infestación para cada mosca de forma independiente; la efectividad de la formulación se calculó usando la fórmula de Abbott. Resultados. La formulación de Ma135 tuvo una eficacia en el control de la infestación de 58% para el caso de H. irritans y de 69% para S. calcitrans, tomando en cuenta las seis semanas de estudio, además de que no causó ningún efecto negativo en la salud de los animales. La reducción del índice de infestación se observó desde la primera semana post-tratamiento (p<0.05) y mantuvo esta tendencia durante todo el estudio. Conclusiones. El presente estudio ha demostrado el potencial de la cepa Ma135 para reducir la infestación simultánea de ambas moscas hematófagas en el ganado bajo condiciones de infestación natural.

Prevalence and risk factors of Neospora caninum infection in ovine flocks of central-western Mexico.

This study, carried out in 13 sheep flocks of central-western Mexico, aimed to identify the prevalence of anti-N. caninum antibodies, to develop a risk analysis of the infection and to estimate the prevalence of parasite DNA in blood. A total of 368 serum and blood samples were subjected to ELISA and PCR tests, respectively, and the association between the prevalence of antibodies and some management factors was estimated. The overall prevalence of anti-N. caninum antibodies was 13.5% [50/368; 95% confidence interval (CI) 10-17], ranging from 2.7 to 90% per flock, and 92% of the farms had seropositive animals. In ewes the prevalence was 14% (48/348, 95% CI 10-17) and in rams 10% (2/20; 95% CI 1- 33). The mean prevalence of Neospora DNA in blood was 27% (99/368, 95% CI 22-31), implying a range between 16 and 82%. In rams, the prevalence was 5% (1/20 95% CI 2-26), while in ewes it was 28% (98/348, 95% CI 23-33). The agreement between the tests was k = 0.19. The presence of other domestic animal species in the farms [odds ratio (OR) 4.4] and the consumption of placental debris, fetuses and stillborn lambs by dogs living in the farms (OR 5.8) were demonstrated to be risk factors.

Neospora caninum Infection during the First Gestation of Holstein Heifers That Consume Food Contaminated Naturally with Zearalenone under Field Conditions.

BACKGROUND: This work studied the natural infection of Neospora caninum during the first gestation of heifers in a dairy farm in animals consuming a ration co ntaminated naturally with Zearalenone (ZEA), and to find out effect of mycotoxin in the levels of estrogen (E) and progesterone (P4) and that's relation to the infection to N. caninum and in the abortions. METHODS: The study was conducted in a dairy farm located in El Llano municipality, in Aguascalientes, Mexico, in 2013. Two groups were formed, the group "A" with 20 seronegative animals to N. caninum, and group "B" with 20 seropositive. Once a month was determined the levels of total IgG to N. caninum, the serum concentration of E and P4, and the level of ZEA in the ration; in cases of abortion, fetal brain samples were taken to identify the presence of N. caninum DNA. RESULTS: In group "A", was observed two subgroups: seronegative (60%) and seroconverted (40%), and three abortions. In group "B", all animals maintain their serostatus, and three animals aborted. All abortions were positive for N. caninum DNA. The level of ZEA in the ration has an average of 426 µg/kg; during the gestation did not identify that animals suffer any alteration in the levels of E or P4. No statistical differences among the studied variables (levels of E and P) in time (nine months of gestation) were detected. It was not identified any interaction with the natural exposure to ZEA intake in any of the groups under study. CONCLUSION: The chronic ingestion of ZEA does not affect serum concentrations of E and P4 during gestation of heifers under study and cannot be related to the infection for N. caninum and the abortion.

Genetic characterization of Neospora caninum from aborted bovine foetuses in Aguascalientes, Mexico.

The cyst-forming protozoan parasite Neospora caninum is one of the main causes of bovine abortion worldwide and is of great economic importance in the cattle industry. Recent studies have revealed extensive genetic variation among N. caninum isolates based on multilocus microsatellite genotyping. Currently, the most extensive study reported is based on the N. caninum genotyping of 96 samples from four countries on two continents (Spain, Argentina, Germany and Scotland) that demonstrate different clusters of multilocus genotypes (MLGs) implicated in cattle abortions as well as the population sub-structuring of N. caninum, which is partially associated with the geographical origin. The aim of this study was to genotype N. caninum from aborted bovine foetuses that originated from Mexico within the region of Aguascalientes and to investigate their genetic diversity. Parasite DNA was detected in 27 out of the 63 analysed foetuses recovered from 10 different herds. Complete or nearly complete profiles based on 9 microsatellite markers were obtained from 11 samples. Diverse N. caninum MLGs were implicated in the occurrence of abortion in each herd. All of the Mexican MLGs differed from the MLGs previously determined for the Argentinean, Spanish, German and Scottish N. caninum populations. The Mexican MLGs failed to cluster by eBURST analyses. The MLG relationships using PCoA showed a close genetic relationship between the Spanish population and a portion of the Mexican population, but a more distant genetic relationship with the Argentinean genotypes. These results demonstrate the genetic diversity of N. caninum in the studied areas that differed from other populations of N. caninum around the world.

Biochemical parameters in the blood of Holstein calves given immunoglobulin Y-supplemented colostrums.

BACKGROUND: In any calf rearing system it is desirable to obtain healthy animals, and reduce morbidity, mortality, and economic losses. Bovine syndesmochorial placentation prevents the direct transfer of bovine immunoglobulins to the fetus, and calves are born hypogammaglobulinemic. These calves therefore require colostrum immediately after birth. Colostrum is rich in immunoglobulins (Ig) and its consumption results in the transfer of passive immunity to calves. The Ig absorption occurs within the first 12 h after birth. Immunoglobulin Y (IgY), derived from chicken egg yolk, has been used in the prevention and control of diseases affecting calves because it is very similar in structure and function to immunoglobulin G (IgG). In the current study, we sought to establish whether administration routes of colostrum supplemented with avian IgY affected passive immunity in calves. RESULTS: No significant differences were observed with respect to route of administration for colostrum. However, we did observe some differences in certain interactions between the various treatments. Calves fed colostrum containing egg yolk had higher levels of TP, ALB, and IgG, along with increased GGT activity. CONCLUSIONS: Our results suggest that supplementing colostrum with egg yolk has a beneficial effect when given to calves, regardless of administration route.

Serosurvey of antibodies against Toxoplasma gondii and Neospora caninum in white-tailed deer from Northern Mexico.

The objective of this study was to determine the seroprevalence of Toxoplasma gondii and Neospora caninum in white-tailed deer from Northern Mexico. Sera from 532 white-tailed deer (Odocoileus virginianus) from three Northern states of Mexico were assayed for antibodies to T. gondii by ELISA and western blot. From these samples, 368 were available to test for N. caninum antibodies by ELISA. The overall prevalence for T. gondii antibodies was 13.9% (74/532; CI(95) 11-17) and for N. caninum 8.4% (31/368; CI(95) 6-12). There was a significant association between positive ELISA results for T. gondii, with management factors within ranches, such number of deer per hectare and geographic location of deer, but none for N. caninum. T. gondii infection in the deer from Guerrero, Coahuila had an increased risk than those from Nuevo Laredo, Tamaulipas (OR, 8.3; CI(95) 1.9-35.4; P<0.05) and ranches with one deer in 15 ha had increased risk of positive association (OR, 2.61; CI(95) 1.5-4.4; P<0.05). These findings may have environmental or public health implications because venison can be an important meat source of T. gondii infections for humans and feral cats.

Infección por Neospora caninum en ganado de carne mantenido en condiciones de pastoreo en el centro-norte de México / Neospora caninum infection in beef cattle reared under grazing conditions in north-central Mexico

Objetive. To determine the seroprevalence of N. caninum antibodies and prevalence of parasite DNA in blood, and estimate the association between seroprevalence and the potential risk of some factors in beef cattle under grazing conditions in north-central Mexico. Materials and methods. Blood samples from 139 cows and only 10 bulls belonging to 13 farms were collected and evaluated by ELISA test to detect antibodies against N. caninum. Furthermore, to determine the presence of parasite DNA, nested PCR probe was performed on blood samples. Association between potential risk factors and seroprevalence was estimated. Results. Overall seroprevalence was 23% (35/149 samples), while the prevalence of parasite DNA in blood was 28% (42/149 samples). Of the 149 animals examined 28 (19%) were positive to both tests (25 cows and 3 bulls). Concordance between tests was k = 0.63. All herds had seropositive animals with positive parasite DNA detection in blood. The only risk factor identified was the presence of dogs (OR= 2.65). Conclusions. This study showed that bovine neospososis should be considered as an important infectious disease in north-central Mexico herds. Therefore, an epidemiological control should be taken into consideration to avoid the negative effect of this disease on mexican beef industry.

Neospora caninum: Detección de ADN en sangre durante la primera gestación de vaquillas infectadas naturalmente / Neospora caninum: DNA detection in blood during first gestation of naturally infected heifers

The aim of the study was to detect the DNA presence of N. caninum in naturally infected animals, at two moments of their first gestation and at parturition, as well as to record the presentation of abortions. Twenty females between 12 to 14 months of age, seropositive to ELISA test, were selected from a dairy farm with presence of this parasitosis. The females were artificially inseminated and blood samples were taken in the first and second third of gestation and during parturition; DNA was isolated and it was analyzed by a single tube nested PCR with specific primers. In the sampling corresponding to the first third of gestation, 7/20 positive cases were observed (35%), in the second 15/20 (75%) and during parturition 10/20 positive cases (50%). From the total of the animals included in this study, three stayed negative to the test in the three samplings (15%), four were always positive (20%), eight were positive in the second sampling but negative in first (40%) and five were positive in the second and negative in first and the third sampling (25%). All animals remained seropositive during the study; four aborted in the last third of gestation. All the live born calves were seropositive to N. caninum.

El objetivo del trabajo fue detectar la presencia de ADN de N. caninum en animales infectados naturalmente, en dos tiempos de su primera gestación y al parto, así como registrar la presentación de abortos. Se seleccionó, en un establo, con presencia de parasitosis, un lote de 20 hembras de entre 12 y 14 meses de edad, seropositivas en ELISA, las hembras fueron inseminadas artificialmente y se tomaron muestras de sangre en el primero y segundo tercios de gestación y al parto; se aisló ADN y se sometió a PCR anidado en un solo tubo con iniciadores específicos. En el muestreo correspondiente al primer tercio de la gestación, se observaron 7/20 casos positivos (35%), en el segundo 15/20 (75%) y al parto 10/20 casos positivos (50%). De los animales incluidos en el estudio, tres se mantuvieron negativos a la prueba en los tres muestreos (15%), cuatro fueron siempre positivos (20%), ocho fueron positivos en el segundo muestreo pero negativos en el primero (40%) y cinco fueron positivos en el segundo y negativos en el primero y tercero muestreos (25%). No se presentó seroconversión en ningún animal durante el estudio; cuatro de ellos presentaron aborto en el último tercio de gestación. Todas las crías nacidas vivas resultaron seropositivas a N. caninum.