Prevalence of Giardia intestinalis and Hymenolepis nana in Afghan refugee population of Mianwali district, Pakistan

Individual and Community-Level Risk Factors for Giardiasis in Children under Five Years of Age in Pakistan: A Prospective Multi-Regional Study

OBJECTIVES

This study aimed to estimate the prevalence of Giardia lamblia infection and identify associated risk factors at both individual and community levels in a pediatric population in different agroecological zones of Khyber Pakhtunkhwa, Pakistan.

METHODS

A community-based cross-sectional study was conducted from March to December 2022. Using stratified sampling, 1026 households were recruited from nine agroecological zones. Stool samples were collected from 1026 children up to the age of five years and processed for detection of Giardia using a commercial ELISA kit. Data on potential risk factors were collected using a pre-structured questionnaire. A multivariable logistic regression model was used to identify risk factors associated with giardiasis.

RESULTS

The study found that the prevalence of giardiasis in the study area was 3.31%. Children aged 13-24 months were found to be at higher risk for giardiasis. Illiterate mothers and fathers attending daycare institutions/kindergartens, mothers not practicing hand washing during critical times, households with companion animals, and homes where stray dogs/cats enter were identified as predictors of giardiasis at the individual level. Children living in sub-mountain valleys use un-piped water, inadequate domestic water storage vessels, drink un-boiled or unfiltered water, live near rubbish heaps or un-paved streets/pathways, and have unimproved latrine facilities were identified as risk factors of giardiasis at the community level.

CONCLUSIONS

The study highlights the need for integrated intervention approaches at both individual and community levels to reduce the incidence of giardiasis in Khyber Pakhtunkhwa, Pakistan. Interventions aimed at promoting behavioral change and providing safe and adequate water sources, combined with individual-level interventions such as hand washing and awareness of giardiasis prevention methods, would be critical to addressing this health concern. Inter-sectoral collaboration between the health sector and other sectors would also be necessary to achieve meaningful progress in reducing the incidence of giardiasis in resource-limited areas.

State-of-the-Art Techniques for Diagnosis of Medical Parasites and Arthropods

Conventional methods such as microscopy have been used to diagnose parasitic diseases and medical conditions related to arthropods for many years. Some techniques are considered gold standard methods. However, their limited sensitivity, specificity, and accuracy, and the need for costly reagents and high-skilled technicians are critical problems. New tools are therefore continually being developed to reduce pitfalls. Recently, three state-of-the-art techniques have emerged: DNA barcoding, geometric morphometrics, and artificial intelligence. Here, data related to the three approaches are reviewed. DNA barcoding involves an analysis of a barcode sequence. It was used to diagnose medical parasites and arthropods with 95.0% accuracy. However, this technique still requires costly reagents and equipment. Geometric morphometric analysis is the statistical analysis of the patterns of shape change of an anatomical structure. Its accuracy is approximately 94.0-100.0%, and unlike DNA barcoding, costly reagents and equipment are not required. Artificial intelligence technology involves the analysis of pictures using well-trained algorithms. It showed 98.8-99.0% precision. All three approaches use computer programs instead of human interpretation. They also have the potential to be high-throughput technologies since many samples can be analyzed at once. However, the limitation of using these techniques in real settings is species coverage.

Health of Special Immigrant Visa holders from Iraq and Afghanistan after arrival into the United States using Domestic Medical Examination data, 2014-2016: A cross-sectional analysis

BACKGROUND

Since 2008, the United States has issued between 2,000 and 19,000 Special Immigrant Visas (SIV) annually, with the majority issued to applicants from Iraq and Afghanistan. SIV holders (SIVH) are applicants who were employed by, or on behalf of, the US government or the US military. There is limited information about health conditions in SIV populations to help guide US clinicians caring for SIVH. Thus, we sought to describe health characteristics of recently arrived SIVH from Iraq and Afghanistan who were seen for domestic medical examinations.

METHODS AND FINDINGS

This cross-sectional analysis included data from Iraqi and Afghan SIVH who received a domestic medical examination from January 2014 to December 2016. Data were gathered from state refugee health programs in seven states (California, Colorado, Illinois, Kentucky, Minnesota, New York, and Texas), one county, and one academic medical center and included 6,124 adults and 4,814 children. Data were collected for communicable diseases commonly screened for during the exam, including tuberculosis (TB), hepatitis B, hepatitis C, malaria, strongyloidiasis, schistosomiasis, other intestinal parasites, syphilis, gonorrhea, chlamydia, and human immunodeficiency virus, as well as elevated blood lead levels (EBLL). We investigated the frequency and proportion of diseases and whether there were any differences in selected disease prevalence in SIVH from Iraq compared to SIVH from Afghanistan. A majority of SIV adults were male (Iraqi 54.0%, Afghan 58.6%) and aged 18-44 (Iraqi 86.0%, Afghan 97.7%). More SIV children were male (Iraqi 56.2%, Afghan 52.2%) and aged 6-17 (Iraqi 50.2%, Afghan 40.7%). The average age of adults was 29.7 years, and the average age for children was 5.6 years. Among SIV adults, 14.4% were diagnosed with latent tuberculosis infection (LTBI), 63.5% were susceptible to hepatitis B virus (HBV) infection, and 31.0% had at least one intestinal parasite. Afghan adults were more likely to have LTBI (prevalence ratio [PR]: 2.0; 95% confidence interval [CI] 1.5-2.7) and to be infected with HBV (PR: 4.6; 95% CI 3.6-6.0) than Iraqi adults. Among SIV children, 26.7% were susceptible to HBV infection, 22.1% had at least one intestinal parasite, and 50.1% had EBLL (≥5 mcg/dL). Afghan children were more likely to have a pathogenic intestinal parasite (PR: 2.7; 95% CI 2.4-3.2) and EBLL (PR: 2.0; 95% CI 1.5-2.5) than Iraqi children. Limitations of the analysis included lack of uniform health screening data collection across all nine sites and possible misclassification by clinicians of Iraqi and Afghan SIVH as Iraqi and Afghan refugees, respectively.

CONCLUSION

In this analysis, we observed that 14% of SIV adults had LTBI, 27% of SIVH had at least one intestinal parasite, and about half of SIV children had EBLL. Most adults were susceptible to HBV. In general, prevalence of infection was higher for most conditions among Afghan SIVH compared to Iraqi SIVH. The Centers for Disease Control and Prevention (CDC) Guidelines for the US Domestic Medical Examination for Newly Arriving Refugees can assist state public health departments and clinicians in the care of SIVH during the domestic medical examination. Future analyses can explore other aspects of health among resettled SIV populations, including noncommunicable diseases and vaccination coverage.

Molecular characterization of Hymenolepis nana based on nuclear rDNA ITS2 gene marker

Introduction

Hymenolepis nana is a zoonotic tapeworm with widespread distribution. The goal of the present study was to identify the parasite in the specimens collected from NorthWestern regions of Iran using PCR-sequencing method.

Methods

A total of 1521 stool samples were collected from the study individuals. Initially, the identification of hymenolepis nana was confirmed by parasitological method including direct wet-mount and formalin-ethyl acetate concentration methods. Afterward, PCR-sequencing analysis of ribosomal ITS2 fragment was targeted to investigate the molecular identification of the parasite.

Results

Overall, 0.65% (10/1521) of the isolates were contaminated with H. nana in formalin-ethyl acetate concentration. All ten isolates were succefully amplified by PCR and further sequenced. The determined sequences were deposited in GenBank under the accession numbers MH337810 -MH337819.

Conclusion

Our results clarified the presence of H. nana among the patients in the study areas. In addition, the molecular technique could be accessible when the human eggs are the only sources available to identify and diagnose the parasite.

Diagnostic Value of Gauze Filtration Technique: A Comparison with Conventional Methods in a Diagnostic Laboratory in Pakistan

Background Intestinal parasites cause significant morbidity and impact human development with an enormous global burden. Diagnosis of intestinal parasites by conventional methods has several limitations. The gauze filtration technique is a relatively simple method that has been shown to identify intestinal parasites with a high sensitivity and specificity. The aim of this study was to determine the diagnostic value of this technique as compared to more conventional methods in a large acclaimed laboratory within Pakistan. Methods A total of 50 stool samples collected for routine diagnostic workup from patients age between 2-70 years were collected from the parasitology section of the Aga Khan University Hospital Clinical Laboratory. A direct wet mount, sedimentation technique, and gauze filtration technique were performed on all of the stool samples, and the sensitivity, specificity, negative predictive value, and positive predictive value were analyzed. Results It was observed that the number of organisms observed by gauze filtration as compared to direct wet mount and sedimentation technique was higher for B. hominis, G. lamblia cysts and trophozoites, and I. bütschlii. Also, the detection rate was significantly higher for B. hominis and G. lamblia cysts using the gauze filtration technique. The sensitivity and specificity of the gauze filtration technique were found to be 95.8% and 100%, respectively. Conclusion There is a significantly better stool sample parasite detection rate using the gauze filtration technique as compared to the conventional sedimentation techniques. The utility of the gauze filtration technique seems economically and technically feasible for diagnostic laboratories in resource-limited settings.

Occurrence and Multilocus Genotyping of Giardia duodenalis in Yunnan Black Goats in China

Giardia duodenalis is an important zoonotic parasite which can parasitize in the intestines of humans and various animals. However, the information about the prevalence and genetic diversity of G. duodenalis in goats in China is limited. It is yet to be known whether Yunnan black goats, a unique goat breed in subtropical Yunnan province, southwestern China, are infected with G. duodenalis. Thus, a total of 907 fecal samples were collected from Yunnan black goats in five regions in Yunnan province, to estimate the prevalence and genotypes of G. duodenalis using a PCR-based approach. The G. duodenalis prevalence is 4.2% (38/907) in Yunnan black goats by nested amplification of the β-giardin (bg) gene, and the genotypes are identified as assemblage E, with 5 novel subtypes (E₁₁-E₁₅). Multilocus sequence typing revealed that 11, 18, and 38 samples were amplifiable on tpi (triose phosphate isomerase), gdh (glutamate dehydrogenase), and bg locus, respectively, and identified three novel multilocus genotypes (MLGs): MLGE9-MLGE11. To our knowledge, this is the first report of G. duodenalis prevalence and genotypes in Yunnan black goats in China, which extended the host range of G. duodenalis and provided basic data for controlling G. duodenalis infection in Yunnan black goats.

Cross-sectional epidemiological investigations of Giardia lamblia in children in Pakistan

BACKGROUND

The prevalence of Giardia lamblia in Pakistani children is currently unknown. The aim here was to evaluate the prevalence and risk factors of Giardia lamblia in children exhibiting diarrhea.

DESIGN AND SETTING

Cross-sectional study at different district healthcare hospitals in Pakistan.

METHODS

A total of 800 samples were collected from children aged 0-10 years. Information regarding personal data, demographic data and supposed risk factors was collected through a structured questionnaire. Giardia lamblia was detected through direct microscopy and antigens through the enzyme-linked immunosorbent assay (ELISA).

RESULTS

The prevalence of Giardia lamblia was 2.75% through direct microscopy and inflated to 9.5% through ELISA. The demographic factors positively associated with occurrences of giardiasis were age (P = 0.035; odds ratio, OR = 1.96; 95% confidence interval, CI = 1.094-3.533), mother's educational level (P = 0.031; OR = 2.67; 95% CI = 1.186-6.045) and father's educational level (P = 0.004; OR = 3.56; 95% CI = 1.612-7.899). Similarly, among the supposed risk factors, rural residency (P = 0.032; OR = 1.76; 95% CI = 1.098- 2.851), absence of proper sewerage system (P = 0.000; OR = 6.60; 95% CI = 4.029-10.841) and unavailability of safe drinking water (P = 0.000; OR = 4.08; 95% CI = 2.207-7.547) were the factors strongly connected with giardiasis. Abdominal discomfort was a prominent clinical sign with 46% frequency.

CONCLUSION

Various risk factors were associated with occurrences of Giardia, thus emphasizing the importance of parents' education, safe drinking water and proper sewerage systems for Pakistani children's health.

Intestinal cestodes

PURPOSE OF REVIEW

Cestodes infections in humans are among the most prevalent parasitosis worldwide. Although tapeworm infection is often asymptomatic, they can be associated with a range of symptoms. The landscape of cestode infections is changing with rapid diagnosis techniques and advanced molecular diagnosis aiding in identification of species specific epidemiology.

RECENT FINDINGS

Traditional descriptions of species by location have been challenged with molecular diagnostic techniques, which show variation in distribution of species, thought to be because of globalization and importation of disease.

MAIN THEMES IN LITERATURE

Epidemiology, molecular diagnostic techniques.

SUMMARY

Infection by tapeworms is often asymptomatic or accompanied by mild symptoms though can occasionally cause severe disease and contribute to anemia and malnutrition. Tapeworm infection is most prevalent in resource-poor countries but the distribution is worldwide. Epidemiology of infection is changing because of molecular diagnostics, which allow more accurate tracking of species.

Intestinal Parasite Infections and Accuracy of Direct Thin and Thick Smear, Formol-Ether Sedimentation, Centrifugal Flotation, and Mini-FLOTAC Techniques Among Patients with Gastrointestinal Tract Disorders from the Greater Cairo Region, Egypt

The aim of the present study was to assess the frequency of intestinal parasitic infection among patients with gastrointestinal tract disorders from the Greater Cairo region, Egypt. In addition, a comparison was made of the accuracy of direct thin and thick smear, formol-ether sedimentation (FEC), centrifugal flotation (CF), and mini-FLOTAC techniques in the diagnosis of infection. Out of 100 patients, the overall prevalence of parasitic infection was 51%. Only 6% had dual infection. Giardia lamblia was the most common parasite (26%), followed by Hymenolepis nana (20%), Entamoeba coli (8%), and Enterobius vermicularis (3%). Except the statistically significant association between E. vermicularis infection and perianal itching and insomnia (P < 0.001), age, gender, and complaints of the examined individuals had no association with prevalence of parasitic infection. Both FEC and CF were equally the most accurate techniques (accuracy = 98.2%, confidence interval [CI] = 0.95-1.0, and κ index = 0.962), whereas the Kato-Katz method was the least accurate (accuracy = 67.5%, CI = 0.57-0.78, and κ index = 0.333). However, mini-FLOTAC-ZnSO₄ was the most accurate for diagnosis of helminthic infection, and FEC was more accurate for diagnosis of protozoal infection (accuracy = 100%, CI = 1.0-1.0, and κ index = 1).

Complete rectal prolapse in young Egyptian males: Is schistosomiasis really condemned?

AIM

To investigate the assumption that schistosomiasis is the main cause of rectal prolapse in young Egyptian males.

METHODS

Twenty-one male patients between ages of 18 and 50 years with complete rectal prolapse were included in the study out of a total 29 patients with rectal prolapse admitted for surgery at Colorectal Surgery Unit, Ain Shams University hospitals between the period of January 2011 and April 2014. Patients were asked to fill out a specifically designed questionnaire about duration of the prolapse, different bowel symptoms and any past or present history of schistosomiasis. Patients also underwent flexible sigmoidoscopy and four quadrant mid-rectal biopsies documenting any gross or microscopic rectal pathology. Data from questionnaire and pathology results were analyzed and patients were categorized according to their socioeconomic class.

RESULTS

Twelve patients (57%) never contracted schistosomiasis and were never susceptible to the disease, nine patients (43%) had history of the disease but were properly treated. None of the patients had gross rectal polyps and none of the patients had active schistosomiasis on histopathological examination. Fifteen patients (71%) had early onset prolapse that started in childhood, majority before the age of 5 years. Thirteen patients (62%) were habitual strainers, and four of them (19%) had straining dating since early childhood. Four patients (19%) stated that prolapse followed a period of straining that ranged between 8 mo and 2 years. Nine patients (43%) in the present study came from the low social class, 10 patients (48%) came from the working class and 2 patients (9%) came from the low middle social class.

CONCLUSION

Schistosomiasis should not be considered the main cause of rectal prolapse among young Egyptian males. Childhood prolapse that continues through adult life is likely involved. Childhood prolapse probably results from malnutrition, recurrent parasitic infections and diarrhea that induce straining and prolapse, all are common in lower socioeconomic classes.

Hymenolepis nana Impact Among Children in the Highlands of Cusco, Peru: An Emerging Neglected Parasite Infection

Hymenolepis nana is the most common cestode infection in the world. However, limited information is available regarding its impact on affected populations. We studied the epidemiology and symptoms associated with hymenolepiasis among children 3-16 years old in 16 rural communities of the highlands of the Cusco region in Peru. Information on demographics, socioeconomic status, symptoms as reported by parents, and parasitological testing was obtained from the database of an ongoing Fasciola hepatica epidemiologic study. A total of 1,230 children were included in the study. Forty-five percent were infected with at least one pathogenic intestinal parasite. Giardia spp. (22.9%) was the most common, followed by Hymenolepis (17.4%), Fasciola (14.1%), Ascaris lumbricoides (6.1%), and Strongyloides stercoralis (2%). The prevalence of Hymenolepis infection varied by community, by other parasitic infections, and by socioeconomic status. However, only years of education of the mother, use of well water, and age less than 10 years were associated with Hymenolepis infection in the multivariate analysis. Hymenolepis nana infection was associated with diarrhea, jaundice, headaches, fever, and fatigue. Children with > 500 eggs/g of stool were more likely to have symptoms of weight loss, jaundice, diarrhea, and fever. Hymenolepis nana infection and age were the only factors retained in the multivariate analysis modeling diarrhea. Hymenolepiasis is a common gastrointestinal helminth in the Cusco region and is associated with significant morbidity in children in rural communities. The impact caused by the emergence of Hymenolepis as a prevalent intestinal parasite deserves closer scrutiny.

Genetic variability among Hymenolepis nana isolates from different geographical regions in China revealed by sequence analysis of three mitochondrial genes

Hymenolepis nana is a common tapeworm that parasitizes in the small intestine of rodent animals and humans. The present study examined the sequence diversity of three mitochondrial (mt) genes namely NADH dehydrogenase subunits 5 (nad5), small subunit ribosomal RNA (rrnS), and ATPase subunit 6 (atp6) of H. nana from mice in different geographical regions of China. A part of the nad5 (pnad5), complete rrnS and atp6 genes were amplified separately from individual H. nana isolates using polymerase chain reaction (PCR) and then sequenced. The sequences of pnad5, rrnS, and atp6 were 710 bp, 704-711 bp, and 516 bp in length, respectively. The A + T contents of the sequences were 70.1-73.5% (pnad5), 70.1-71.7% (rrnS), and 76.6-77.9% (atp6). Sequence variation within H. nana was 0-1.4% for atp6, 0-1.7% for rrnS, and 0-0.7% for pnad5. The inter-specific sequence differences between H. nana and Hymenolepis diminuta were significantly higher, which was 31.6-31.7% (pnad5), 16.1-17.6% (rrnS), and 26.5-27.1% (atp6). Phylogenetic analysis based on the combined three sequences using the maximum parsimony (MP) method supported that H. nana is a species complex or "cryptic" species. These findings demonstrated clearly the usefulness of the three mtDNA sequences for population genetics and systematic studies of H. nana of human and animal health significance.