Study on rodents infestation in Alexandria and prevalence of Trichinella spiralis infection among them.

Rodents were monthly collected from the six districts of Alexandria all year round using live traps. The 1025 collected rodents were divided according to species, gender, age, and weight El-Amryia and El-Montaza were the most infested districts, while West, East, Middle and El-Gomrok Districts were the lowest infested ones. Rallus norvegicus was the highest abundant species in the city (41.9%) followed by R. rattus (37.2%), then Mus musculus (20.9%). There was no difference in abundance of rodents during summer compared with winter. Meanwhile, males represented 57.6% of the total collected rodents. Most of the collected rodents were < or = 2 months old (63.8%) or light weighed (61.6%) however, number of caught rodents became less and less as age or weight increased. Concerning El-Amryia and El-Montaza Districts where abattoirs are located, number of collected rodents from and around the abattoirs represented 70.4% of the total collected rodents compared with 29.6% collected from and around the houses of the same districts. The total prevalence of T. spiralis infection among collected rodents using digestion technique was 13.3%. El-Amryia, El-Montaza, West and El-Gomrok Districts were, in order, the only infected districts. Neither gender nor season of collection has influence on the prevalence of infection. The present study proved the role of abattoirs in the prevalence of T. spiralis infection. However, high prevalence of T. spiralis infection was detected among higher age or higher body weight groups of rodents. Sensitivity of the digestion diagnostic technique is proved compared with compressorium diagnostic technique. Nevertheless, diaphragm was the most sensitive site for detection of light infection in all studied rodents followed by thigh then tongue; expressed as number of larvae per gram tissue.