Assessing the burden of intestinal parasites affecting newly arrived immigrants in Qatar

Abstract

BackgroundIn the last decades, the enormous influx of immigrants to industrialized countries has led to outbreaks of parasitic diseases, with enteric infections being amongst the most frequently encountered. In its strategy to control such infection, Qatar has established the Pre-Employment Certificate (PEC) program which requires medical inspection before arrival in Qatar and which is mandatory for immigrant workers travelling to the country. To assess the reliability of the PEC, we conducted a survey of intestinal parasites, based on examination of stool samples provided by immigrant workers (n = 2,486) recently arrived in Qatar.ResultsOverall prevalence of helminths was 7.0% and that of protozoa was 11.7%. Prevalence of combined helminths was highest among the western Asians and the highest prevalence of combined protozoan parasites was among workers from North to Saharan Africa. Analysis of temporal changes showed an increasing trend of protozoan infections over the investigated 3 years. A major contribution to this temporal change in prevalence came from Blastocystis hominis as well as from other protozoan species: Giardia duodenalis and Endolimax nana. Analysis of the temporal trend in species richness of the protozoan species showed a significant increase in the mean number of species harboured per subject across this period.ConclusionThe increase of protozoan infections over recent years raises some concerns. It suggests that screening protocols for applicants for visas/work permits needs to be revised giving more careful attention to the intestinal protozoan infections that potential immigrants may harbor.

Socio-demographic influences on the prevalence of enteric helminth and protozoan infections in newly arrived migrant workers in Qatar

“…Because of the number of factors involved, this second phase was conducted in three separate stages. First model 1 was fitted with the significant familial factors from phase 1, and then a second model (model 2) was fitted with the environmental factors, and in each case also including age class and region of origin of subjects as these had been shown earlier to have had a significant effect on INFECTION (14). In a third stage the significant factors from models 1 and 2 were included in model 3 that also incorporated age class and region of origin.…”

“…However, fitting univariate models does not allow the influence of confounding factors and their interactions to be identified, so in the second phase of our analysis we fitted all the significant effects from phase 1 into multifactorial models and combined these with age class and region of origin, which had been shown in our earlier paper to have had an influence on parasitic infections in these same individuals (14).This showed that many of the factors identified by univariate analysis are likely to have arisen through confounding interactions between fitted factors. The minimum sufficient models thus generated showed that the prevalence of combined helminth infections was influenced only by An earlier study conducted in Sharjah investigated intestinal protozoan infection rates among both expatriates and locals, and the infection rate was reported as 7.7% (17).…”

“…The significant factors identified in the first phase as affecting the prevalence of combined helminth infections were age class of subjects, the number of siblings, mother's education and household contents index. Age class of subjects was reported as a significant factor in this data-set in our earlier publication (14). Following backward selection and model simplification, the minimum sufficient GLM model comprised only the main effects of age class (Wald χ 2 3 =12.2, P=0.007) and a weak effect of the mother's education level (Wald χ 2 3 =9.7, P=0.046) as factors influencing the prevalence of helminths in this data-set.…”

“…We conducted a retrospective cross-sectional study on the prevalence of intestinal protozoa in Qatar among the expatriates in certain jobs (food handlers, housemaids, white collar, blue collar, and pink collar workers). Briefly, 2,486 subjects from 24 countries were screened during the period 2012-2014. sub-Saharan Africa (n=123), as described by Abu Madi et al (14). The methods used for coproscopy have been fully described in Abu Madi et al (15).…”

Coproscopy and molecular screening for detection of intestinal protozoa

“…In Qatar, the most widely used methods for surveillance of enteric infections among newly arrived and resident workers still rely on coproscopy [ 15 ]. In this paper we assess a method based on PCR as an alternative to examination of stool samples by microscopy.…”