Characterization ofAscarisfrom Ecuador and Zanzibar

Abstract

To shed light on the epidemiology of ascariasis in Ecuador and Zanzibar, 177 adult worms retrieved by chemo-expulsion from either people or pigs were collected, measured and subjected to polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) analysis of the ribosomal internal transcribed spacer (ITS) region. Upon double digestion with RsaI and HaeIII, PCR-RFLP analysis revealed the presence of A. lumbricoides in people and A. suum in pigs in Ecuador. In contrast, while there are no pigs on Zanzibar, of the 56 worms obtained from people, one was genotyped as A. suum. No additional genetic variation was detected upon further PCR-RFLP analysis with several other restriction enzymes. Upon measurement, worm mass and length differed by location and by species, A. suum being lighter and longer. While there is no evidence to suggest zoonotic transmission in Ecuador, an enduring historical signature of previous zoonotic transmission remains on Zanzibar.

Molecular analysis of human- and pig-derivedAscarisin Honduras

“…In addition, differences within the ITS sequence seem to provide a genetic structure similar to those given by other molecular markers for Ascaris worms (Anderson, 1995; Arizono et al , 2010; Bendall et al , 2011; Peng & Criscione, 2012; Dutto & Petrosillo, 2013; Sparks et al , 2015). Despite the low nucleotide divergence within the rDNA region, Nadler & Hudspeth (2000) showed that this gene includes six and one unambiguous autapomorphic characters in A. lumbricoides and A. suum , respectively.…”

“…Similar results have been found in Ecuador, where Sparks et al . (2015), using ITS as the molecular marker, did not find any cross-infections among humans and pigs. These data, along with our own results, suggest that although natural or experimental cross-infections are plausible, they are less frequent than host-specific infections in environments in which both species coexist (Jungersen et al , 1996; Bendall et al , 2011; Miller et al ., 2015).…”

The molecular speciation of soil-transmitted helminth eggs collected from school children across six endemic countries

“…Introduction). Moreover, in some countries pigs are already rare or absent due to cultural habits (e.g., Ethiopia and Tanzania (Pemba)), and hence zoonotic transmission is already unexpected, though pig-to-human transmission cannot be entirely excluded 18. This is in contrast for animal hookworm species, were evidence of zoonotic transmission was absent, particularly for A. ceylanicum in Asian countries.…”

“…In addition, they highlight important geographical variation in the distribution of animal STH species in humans. Ascaris infections in developed countries, where human STH species are non-endemic, are almost exclusively caused by pig-to-human transmission (e.g., USA13; Denmark14; UK15; Japan16), whereas zoonotic transmission has only been occasionally reported in countries where STHs pose an important burden on public health, such as Uganda17 (<1% of the human derived Ascaris worms were of pig origin), Zanzibar18 (2%) and China19 (14%). Zoonotic Trichuris infections have been reported in Uganda20 (10% of the human derived Trichuris worms were of pig origin) and Thailand8 (11% of the speciated Trichuris egg isolates from human stool contained T. vulpis ).…”

Ascaris lumbricoides and its almost deadly complication

“…Infections are most common in the developing world [ 2 ], with higher prevalence among children [ 4 ]. In countries like Ecuador, where sanitary conditions are poor in some regions, people are at a higher risk of parasitic infections [ 6 ]. Our patient lives in the Amazon region with limited access to drinking water, which probably contributed to her infection.…”