Echinococcus multilocularis – a zoonosis of anthropogenic environments?

Abstract

Transmission of the fox tapeworm Echinococcus multilocularis, the causative agent of human alveolar echinococcosis, is known to depend on various environmental factors which are subject to human influence. Epidemiological data suggest that in most endemic regions anthropogenic landscape changes (e.g. deforestation and agricultural practices) have led to more favourable conditions for the parasite's animal hosts, especially arvicolid rodents, thereby increasing the risk for parasite transmission and human disease. Examples are the conversion of forests or crop fields into meadows and pastures in Europe, China and North America, and overgrazing of natural grassland in central Asia. Other anthropogenic factors include interference with host population densities by wildlife disease control, changing hunting pressure and provision of new habitats, e.g. in urban areas. Domestic dogs may, under certain conditions, get involved in the otherwise largely wildlife-based transmission, and thereby greatly increase the infection pressure to humans. The introduction of neozootic host species may increase transmission, or even initiate the parasite's life-cycle in previously non-endemic regions. Lastly, the parasite itself may be accidentally introduced into non-endemic areas, if suitable host populations are present (e.g. in northern Japan).

Genotyping of Echinococcus granulose in Samples of Iraqi Patients

“…But the domestic dog as a definitive host for E. granulosus plays an important role in the spread of infection in the Middle East countries via contamination of environment. Sheep, goats, cattle, camels, buffaloes, pigs, and donkeys have been repeatedly found infected with hydatid cysts in Iran, Iraq,Jordan, Lebanon, Syria, Kuwait, and Saudi Arabia (3)(4)(5)(6)(7)(8)(9)(10)(11). PCR was used as a suitable tool for the characterization of E. granulosus strains in different studies.…”

“…Genotype of infecting strain affects the fertility rate of the cysts in the intermediate hosts and thereby the infectivity of strain for the subsequent hosts in the table (4)(5)(6)(7)(8)(9)(10), the present findings, study the association between echinococcus genotypes and related organ, the current study shows 26(43%) G4 (Horse Strain), 18(30%) G1/G/G3 (sheep strain), 4(7%) G6/G7 (camel and pig strain), 12(20%) G5 (cattle strain).…”

“…Our finding shows 4(7%) G1/G/G3 sheep strain, 6(107%) G4 horse strain, the total genotypes were recorded in the various organ included the following, 18(30%) were G1/G/G3, 26(43%) were G4, 4(7%) were G6/G7 and finally 12(20%) were G5, these results were statistically not significant (p>0.05), and in agreement with Sharmal et al, (2013). In table (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14), our finding, were shows the gene maker distribution anhydrate cyst patients genotypes as he follows: 16(26%) were EF1a (796bp) gene, (2,3%) were CaL (1001bp) gene, while 26(43%) Cox1(124bp) gene, 4(6.61) were ATP-6(1041 bp) gene, 4(6.6%) were Nad1, (339bp) gene, 8 …”

“…The poorly characterized strain G9 is closely related to E. canadensis (G7) [7] and the existence of G9 as aseparate genotype remains still controversial [8,9].…”

Infection of foxes byEchinococcocus multilocularisin urban and suburban areas of Nancy, France: influence of feeding habits and environment

“…Even though cats' behaviour could favour their infection, among rodents predation, their physiology presents a lower susceptibility to infection and eggs excretion (Kapel et al, 2006). Contribution of domestic carnivores to human exposure in Europe is still unclear and their proximity to man may pose a major zoonotic risk (Petavy et al, 2000;Romig et al, 2006b). In Europe, the red fox is the main source of environmental contamination (Deplazes & Eckert, 2001).…”