The prevalence of intestinal parasitic infections among Kosovar and Serbian school-children in Kosovo

Despite a spectacular advance in the diagnosis and management of diseases, intestinal parasitic infections remain a major public health issue globally (Keiser and Utzinger, 2010). It is estimatedthat more than two billion people world wide are infected with atleast one species of intestinal parasite and over five billion peoplelive in countries where helminths and protozoa are endemic (Kucik­ et al., 2004). The risk of infection is particularly high in areas with poor sanitation because poor hygiene and the lack of adequate sanitaton facilities encourage the spread of food and waterbornediseases (Hotez et al., 2007). There are a number factors which facilitate the spread of parasitic infections both in the developingand the industrialized world; these include low socio economic status, mass migrations, and the presence of hosts in ecosystems (reservoirs of parasites) (Ali et al., 2014; Ojha et al., 2014). The spectrum of clinical symptoms in parasitic infections is extremelywide and may vary from asymptomatic cases through diarreas to cachexia leading to severe anemia (Korzeniewski and Kurpas, 2016). ­Microscopic ­examination ­is ­still ­the ­gold ­standard­ for ­the­ diagnosis of intestinal helminths and protozoa making it possible to detect parasites at their different developmental stages (cysts, trophozoites, larvae, ova) (Myjak et al., 2011). In Europe, high rates of parasitic infections are reported from the countries which are listed in the third and fourth quartile according to gross domestic product per capita (GDP $1 809 – $17 630) (Hotez and Gurwith, 2011); Kosovo ranks in the 4^th quartile. The exact prevalence of parasitic infections in Kosovo is not clear because the country lacks organized epidemiological screening. In 2001, a study was conducted to establish the etiology of diarrhea in 45 Kosovar children (Kosovska Mitrovica). It revealed that 40 % of the diarrhea cases in the study group were associated with Giardia intestinalis (Quamilè et al., 2011). Another study aimed at assessing the prevalence of parasitic infections in Kosovo was conducted by the authors of the present article in 2015. The study group consisted of 632 Kosovars (children and adults) living in the municipality of Kaҫanik located in southern Kosovo. We found that 12 % of the study population had asymptomatic parasitic infections, mainly Giardia intestinalis infection (10 % of the infected individuals) (Korzeniewski and Augustynowicz, 2017). Kosovo has a population of around 2 million people. The majority of its residents are Albanian, but there are also some significant ethnic minorities living in the country, of which the Serbian minority is the largest (140,000).

The aim of this study was to assess the prevalence and distribution of species of intestinal parasites in the Balkans on the example of Kosovar and Serbian residents from the region of Gnjilane in eastern Kosovo, where the epidemiology of intestinal parasitic infections remains unknown.

The research project was approved by the Bioethics Committee at the Military Institute of Medicine in Poland (Decision No. 72/ WIM/2017) under the Declaration of Helsinki and in line with the EU provisions on Good Clinical Practice for conducting clinical trials and testing medicinal products signed by the Polish Bioethics Committee.

Following the microscopic examination of 1,680 stool specimens (two samples taken from each of the 840 subjects) by three different light microscopy methods we found that the total prevalence of intestinal parasites was 19.1 % in Kosovar (n=530) and 4.2 % in Serbian school-children (n=310). The study revealed that 101 Kosovar children were infected with pathogenic intestinal parasites; a total of 103 infections were detected (two cases of co-infections). The most frequently detected intestinal parasites included Giardia intestinalis (14.9 % study subjects), Ascaris lumbricoides (1.5 %) and hookworm (1.5 %) (Table 1).

A total of 13 Serbian children were found to be infected with intestinal parasites. Giardia intestinalis (1.9 % of the study group) and Ascaris lumbricoides (1.0 %) were predominant (Table 2). Infections with non-pathogenic intestinal parasites, e.g. Enatmoeba coli, Endolimax nana, Chilomastix mesnili (found in both examined groups) were not taken into consideration and are not discussed in this paper.

Current epidemiological situation of intestinal parasitic infections (IPI) in Kosovo is unknown and presented study remains one of few analyses in the field of intestinal parasitology in this region. Population screening to assess the prevalence of intestinal parasites have been carried out in the neighboring countries, e.g. in Albania and Serbia. The study of Sejdini et al. (2011) involving 321 children (aged 7 – 16 years) living in the counties of Tirana and Elbasan in central Albania demonstrated the overall IPI incidence of 19.0 %, the most prevalent being Giardia intestinalis (10.9 %), hookworm (5.6 %), and Ascaris lumbricoides (1.9 %). A different screening study performed by Spinelli et al. (2006) in 277 asymptomatic subjects from central Albania found that 24.2 % of the study group were infected with pathogenic protozoa and helminths, including Trichuris trichiura (12.3 %), Giardia intestinalis (11.2 %), Hymenolepis nana (1.8 %) and Ascaris lumbricoides (1.1 %). The authors’ study involving 530 asymptomatic Kosovar school-children from the Gnjilane region demonstrated a similar overall incidence of IPI (19.1 %), where the most commonly identified parasites included Giardia intestinalis (14.9 %), hookworm (1.5 %) and Ascaris lumbricoides (1.5 %).

According to the research studies conducted in Serbia, the rates of infections with intestinal parasites in the local population are relatively low. A multicenter screening of 6,645 asymptomatic school-children, aged 7 – 11 years, from 115 settlements in 20 different regions of central Serbia (including Belgrade, Kragujevac, Lučani, Bor, Žagubica, Sjenica, Novi Pazar, Valjevo, Aleksandrovac, Pirot, Bosilegrad, Ivanjica, Golubac, Užice, Kladovo, Negotin, Kraljevo, Gornji Milanovac, Kruŝevac, and Čačak) found the overall prevalence of Giardia intestinalis infections to be 6.1 %. (Nikolić et al., 2011). The authors’ study conducted in the period between 2017 and 2018 among 310 asymptomatic Serbian school-children from the Gnjilane region in eastern Kosovo, demonstrated the overall incidence of IPI at 4.2 %, with Giardia intestinalis (1.9 %) and Ascaris lumbricoides (1.0 %) being predominant. Examination of 2,440 Serbian travelers returning from tropical and subtropical destinations revealed infections with intestinal parasites in 1.2 % patients only, mainly Entamoeba histolytica sensu lato and Giardia intestinalis (Dakić et al., 2011). In recent years, a majority of studies into the prevalence of intestinal parasites in humans that are carried out in Europe are primarily focused on the incidence of Cryptosporidium spp. and Giardia spp. Serbia is one of the countries participating in IPI surveillance (the number of reported giardiasis cases in the country fell from 4.6/100,000 in 2005 to 1.1/ 100,000 in 2014) (Plutzer et al., 2018). Unfortunately, there is no reliable data available as to the prevalence of intestinal parasitic infections in Kosovo.

Current epidemiology of intestinal parasites in Kosovo is unknown. The study involved asymptomatic Kosovar and Serbian school-children living in the same ecosystem of the Gnjilane region (eastern Kosovo) and demonstrated that the prevalence of intestinal parasitic infections in Kosovars is significantly higher in comparison to Serbian children, which may be the evidence of some differences in the quality of health care and sanitation as well as feed hygiene between these two communities.