The carriage of larval echinococcus multilocularis and other cestodes by the musk rat (Ondatra zibethicus) along the Ourthe River and its tributaries (Belgium).

In Belgium, the carriage of Echinococcus multilocularis by the red fox (Vulpes vulpes) can be very high in some areas. This study was designed to evaluate the carriage of the larval form of E. multilocularis and other cestodes in a musk rat (Ondatra zibethicus) population trapped along the Ourthe River (southeastern Belgium). Six hundred fifty-seven musk rats were necropsied, and the larval cestodes of the abdominal and pleural cavities were identified. For E. multilocularis, the fertility of the cysts was verified in 58 liver samples. The following species were found: Taenia taeniaeformis (65.8%), Taenia martis (22.2%), E. multilocularis (22.1%), Taenia polyacantha (2.6%), and Taenia crassiceps (0.9%). Results were analyzed according to the site of capture (upper, middle, and lower Ourthe). There was a highly significant relationship between the carriage of E. multilocularis and the site of capture (the prevalence being higher in the upper part of the river). This difference could be due to different geoclimatic conditions. All but one hepatic lesion were found to contain protoscoleces of E. multilocularis (98.8%). The musk rat is probably infected through the consumption of plant material contaminated by the fox's feces. The red fox can occasionally prey on musk rats, but the musk rat cadavers that are left on the river banks by the trappers are probably also consumed. This could favor the maintenance of E. multilocularis life cycle. In conclusion, the musk rat seems to be highly susceptible to E. multilocularis and in Belgium could play the role of reservoir; when present this species could represent an inexpensive and sensitive bioindicator for the study and monitoring of the zoonosis.

Echinococcus multilocularis in Belgium: prevalence in red foxes (Vulpes vulpes) and in different species of potential intermediate hosts.

Echinococcus multilocularis causes a rare but potentially lethal zoonotic infection in humans. This tapeworm is known to be endemic in foxes in several countries of Western and Central Europe. In Western Europe, the common vole (Microtus arvalis) and the water vole (Arvicola terrestris) are considered to be the most important intermediate host species of this cestode whereas the red fox is by far the most important final host. The purpose of this study was to provide data on the prevalences in Wallonia (Southern part of Belgium) both in the red fox and in different potential intermediate hosts. A total of 990 red foxes were examined between January 2003 and December 2004 for the presence of E. multilocularis. The average prevalence was 24.55% (22.38-27.87). Out of 1249 rodents or insectivores belonging to the species Apodemus sylvaticus, Arvicola terrestris, Clethrionomys glareolus, Microtus arvalis, Microtus agrestris and Sorex araneus, only one M. arvalis (out of 914-0.11% (0.003-0.61) and one C. glareolus (out of 23-4.3% (0.1-21.9) were found to be infected. However, the muskrat (Ondatra zibethicus) seems to be a good intermediate host as 11.18% (9.72-12.76) of the animals (n=1718) were found to be infected. A positive correlation was found between the prevalences in foxes and in muskrats in each of the different geological regions. This study indicates that the muskrat is highly sensitive to this zoonotic tapeworm and could perhaps represent a good bioindicator when studying the epidemiology of this parasitic infection in Belgium and in other countries where the muskrat is present.

Echinococcus multilocularis and Toxocara canis in urban red foxes (Vulpes vulpes) in Brussels, Belgium.

During the last decades, European red foxes (Vulpes vulpes) have been implicated in the transmission of several viral or parasitic pathogenic agents to domestic animals and humans. In urban areas, risks of zoonoses transmission are likely to increase as a result of a higher rate of intra- and inter-species contacts. Foxes occur on 35% of the Brussels-Capital Region area and local densities reach up to 4 family groups per square kilometre. According to the directive 2003/99/ECC, a first survey for the presence in foxes of Echinococcus multilocularis and Toxocara canis was conducted in Brussels from 2001 to 2004. None of 160 foxes were found to be infected with E. multilocularis and 24 of 134 foxes were found to be infected with T. canis. Considering numbers of examined foxes, the sensitivity and the specificity of tests used for diagnosis, the 95% credibility intervals for the true prevalence of E. multilocularis and T. canis were estimated in a Bayesian framework to be 0 to 1.87% (median value of 0%) and 12.7 to 26% (median value of 18.7%), respectively. For T. canis, a significantly higher risk to be a carrier occurs in cubs and a significantly lower risk in adults.

Detection of Echinococcus multilocularis in wild boars in France using PCR techniques against larval form.

Recently, new data have been collected on the distribution and ecology of Echinococcus multilocularis in European countries. Different ungulates species such as pig, goat, sheep, cattle and horse are known to host incomplete development of larval E. multilocularis. We report a case of E. multilocularis portage in two wild boars from a high endemic area in France (Department of Jura). Histological examination was performed and the DNA was isolated from hepatic lesions then amplified by using three PCR methods in two distinct institutes. Molecular characterisation of PCR products revealed 99% nucleotide sequence homology with the specific sequence of the U1 sn RNA gene of E. multilocularis, 99 and 99.9% nucleotide sequence homology with the specific sequence of the cytochrome oxydase gene of Echinococcus genus and 99.9% nucleotide sequence homology with a genomic DNA sequence of Echinococcus genus for the first and the second wild boar, respectively.