Academic Journal of Nawroz University (AJNU), Vol.11, No.4, 2022 This is an open access article distributed under the Creative Commons Attribution License Copyright ©2017. e-ISSN: 2520-789X https://doi.org/10.25007/ajnu.v11n4a1597 147 Prevalence and risk factors of Giardia lamblia among infants and children in Duhok province/Kurdistan Region, Iraq Idrees Yousif Ali 1 , Wijdan Mohammed Salih Mero 2 , Ahmed Basheer Mohammed 3 1,2,3 Department of Biology, Faculty of Science, Zakho University, Zakho, Duhok Province, Kurdistan Region, Iraq 2 Scientific Research Center, Nawroz University, Duhok Province, Kurdistan Region, Iraq ABSTRACT The study was performed on 504 stool samples from infants and children with diarrhea who attended laboratories at Zakho General Hospital, Heevie Pediatric Hospital, Chamisku and Bersive 1 camps, and children who did not have diarrhea in various primary schools in Zakho between August 2021 and the end of July 2022. The study focused on 1 month of age to 15 years old. The collected stool specimens were examined macroscopically followed by microscopic examination using wet mount and concentration methods. The microscopic findings revealed an overall prevalence of Giardia lamblia at a rate of 6.15% (31/504), with slightly but non-significantly higher infection rate in males than in females (6.71% vs. 5.43%). The highest rate of infection was noted among the age group >3-6 years, while the lowest rate was among the age group >12-15 years, which were 11.76% and 1.45%, respectively. The infection rate was also twice as high among rural residents as compared to urban ones (10.34% and 3.32%), respectively. Infants and children who drink tap water had a high infection rate, whereas those drinking bottled water had a lower infection rate (8.05% and 1.92%), respectively. The infection rate was non- significantly higher in families with more than 6 members than in those with less than 6 members (7.06% and 5.22%) respectively. In terms of monthly infection distribution, the highest prevalence was reported in July (11.29%), while the lowest rate was recorded in February (2.27%). Finally, the statistical analysis revealed a significant relationship between infection and age group, residence, as well as the types of drinking water consumed, but non-significant relationship between infection and gender, number of family members and months of sample collection. KEY WORDS: Giardia lamblia, prevalence, infants and children, risk factors, Duhok province, Kurdistan region, Iraq. 1. Introduction Giardia lamblia, also known as Giardia intestinalis or Giardia duodenalis, is the most common and one of the top ten protozoan parasite infecting human small intestine and is a major cause of enteric infection worldwide, particularly in children (Farthing and Kelly, 2005; Kayser et al., 2005). Furthermore, giardiasis has a significant impact on human health in tropical and subtropical areas (Maru, 2015). Giardia lamblia affects individuals all over the world, even those in rich nations, but it is more common in places with poor sanitation (El-Safi et al., 2013), causing more than 280 million new human cases each year (Einarsson et al., 2016). In developing nations, the frequency of infection ranges from 10% to 50%, particularly among young individuals in underprivileged areas (Daly et al., 2010). Giardia lamblia spreads primarily via contaminated water or food. Other contributing factors include unsanitary personal habits, unsafe water supplies, overcrowded housing, poor environmental sanitation, unsanitary living conditions, and lower economic conditions (Kayser et al., 2005) Giardiasis can vary from asymptomatic to chronic or severe diarrhea and even persistent diseases. Asymptomatic hosts also can shed infectious cysts and serve as a disease transmission vector (Hanevik et al., 2009). The clinical symptoms of G. lamblia infection range from the lack of pathological indications to the emergence of diarrhea, stomach cramps, flatulence, losing weight, vomiting, and nausea (Kuick, 2004) Giardiasis can be diagnosed by many methods such as passing a foul-smelling, clumsy, pale, non-bloody, mucoid, or watery stool (Despommier et al., 2017). Giardiasis can be detected by direct microscopic examination of a wet mount or the use of Lugol's