Statistical approach to Trichinella infection in horses handled by rural slaughterhouses across five distinctive socioeconomic regions in Mexico

Serology survey of Ascaris suum and Trichinella spiralis in rural pigs in Southwestern Mexico

BACKGROUND

Parasitic diseases of pigs are a public and veterinary health problem. Helminths influence pork production, whereas backyard pigs can transmit these parasites.

OBJECTIVES

This work aimed to investigate the prevalence of antibodies against Ascaris suum and Trichinella spiralis in backyard pigs from Jamiltepec, Region de la Costa, Oaxaca, in Southwestern Mexico.

METHODS

Six hundred sixty-four serum samples were obtained from backyard pigs from 23 rural villages distributed in 5 municipalities; samples were taken in a non-probabilistic manner with the owner's consent. The presence of serum antibodies against a total extract of A. suum adult worm was determined by ELISA. In contrast, antibodies to the excretion-secretion products of the T. spiralis muscle larva were determined by Western blot.

RESULTS

The global seroprevalence for A. suum was 5.12% and 2.41% for T. spiralis; however, antibodies were only found in 8 villages and distributed in 3 municipalities. The highest frequency of positivity for Ascaris was found in the municipality of Santa Catarina Mechoacán (13.01%), whereas, in Santa María Huazalotitlán, the highest frequency of positivity for Trichinella was found (5.75%). In San Andrés, frequencies were 7.23% and 4.82%, respectively. No statistical differences were observed between populations.

CONCLUSIONS

Our data suggest that helminth transmission is restricted by locality. However, further studies must be conducted to understand the factors limiting this transmission to promote pork meat production in parasite-free zones.

Kinetics of Eosinophils during Development of the Cellular Infiltrate Surrounding the Nurse Cell of Trichinella spiralis in Experimentally Infected Mice

We study the kinetics of eosinophils during the development of the cellular infiltrate surrounding the nurse cell of Trichinella spiralis (T. spiralis) in experimentally infected mice. Male CD1 mice were experimentally infected with 50 viable muscle larvae of the MSUS/MEX/91/CM-91 T. spiralis strain. Tongues and diaphragms were obtained daily from days 13 to 39 post infection. Diaphragms were compressed and subjected to Giemsa stain. Tongues were histologically sectioned and stained with erythrosine B or hematoxylin and eosin. The cellular infiltrate and the nurse cell-larva complex were detected by optical microscopy since day 16 post infection. The size of the larva increased exponentially during the course of the infection. The kinetics of eosinophils showed a multimodal trend, with a bimodal predominance. The maximum peaks were reached on days 21 and 27 post infection. The results of this study demonstrate that eosinophils occur abundantly in two transcendent moments of the T. spiralis life cycle: first, when the stage 1 larva invades the myocyte and second when the nurse cell-larva complex has been fully developed. These results help one to understand the immunobiology of T. spiralis, highlighting the importance of eosinophils in the survival of the larva in skeletal muscle. Further studies are needed to characterize the cell populations that comprise the cellular infiltrate during the development of the mother cell.

Helminths of the Wild Boar (Sus scrofa) from Units of Conservation Management and Sustainable Use of Wildlife Installed in the Eastern Economic Region of Mexico

Wild boars (Sus scrofa) were introduced in Mexico for sport hunting and meat trading for human consumption, but the available data regarding their role in pathogen transmission are limited. This research and field work aimed to identify the helminths of the wild boar produced in three units of conservation management and sustainable use of wildlife placed in the eastern economic region of Mexico. Samples of feces and serum were collected from 90 animals that came from three different ranches. Stool examination and antibody determination to Fasciola hepatica, Taenia crassciceps, Ascaris suum, Toxocara canis (ELISA), and Trichinella spiralis (Western blot) were performed. In addition, 30 diaphragm samples from one ranch were obtained for artificial digestion. Eggs of Strongyloides sp. (72.2%), Metastrongylus sp. (57.7%), Oesophagostomum sp. (53.3%), and Trichuris sp. (37.7%) were found in addition to oocysts of Eimeria sp. (75.6%). Antibodies to Fasciola (8.9%), Taenia (4.4%), Ascaris (32.2%), Toxocara (20%), and Trichinella (5.5%) were found. The eggs of Strongyloides and Oesophagostomum were associated to female hosts. One nematode larva was found by artificial digestion. This is the first report to identify helminths from wild boars in Mexico. In addition, this study identifies the potential risk of the wild boar as a transmission channel of parasites that can have an impact on public health.