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Archer J, Cunningham LJ, Juhàsz A, Jones S, Doull F, LaCourse JE, Mainga B, Makaula P, Kayuni SA, Musaya J, Stothard JR. Molecular Epidemiology and Assemblage Typing of Giardia duodenalis in School-Age Children Situated along the Southern Shoreline of Lake Malawi, Malawi. Am J Trop Med Hyg 2023; 109:626-639. [PMID: 37549892 PMCID: PMC10484258 DOI: 10.4269/ajtmh.23-0156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 06/16/2023] [Indexed: 08/09/2023] Open
Abstract
Almost all human giardiasis infections are caused by Giardia duodenalis assemblages A and B. Differentiation between human infections with these assemblages, as well as between single-assemblage (A or B) and mixed-assemblage (A and B) infections, is therefore needed to better understand the pathological impact of infection with either, or both, assemblages. We assessed the prevalence of G. duodenalis assemblages A and B using 305 fecal samples provided by school-age children situated along the southern shoreline of Lake Malawi. Concurrently, intestinal pathology data were also collected to test for association(s) between assemblage infection status and intestinal health. Prevalence of G. duodenalis infection was 39.3% by real-time polymerase chain reaction. Of all identified infections, 32% were single G. duodenalis assemblage A and 32% were single G. duodenalis assemblage B, whereas 33% were mixed-assemblage infections. Fifteen unique G. duodenalis assemblage A and 13 unique G. duodenalis assemblage B β-giardin haplotypes were identified. There was a positive association between single infection with G. duodenalis assemblage B and both self-reporting of abdominal pain (odds ratio [OR]: 3.05, P = 0.004) and self-reporting of diarrhea (OR: 3.1, P = 0.003). No association between single infection with assemblage A and any form of intestinal pathology was found. Additionally, there was a positive association between mixed-assemblage infections and self-reporting of abdominal pain (OR: 3.1, P = 0.002). Our study highlights the importance G. duodenalis assemblage typing and reaffirms the need for improved access to water, sanitation and hygiene infrastructure in rural areas of low- and middle-income countries.
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Affiliation(s)
- John Archer
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Lucas J. Cunningham
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Alexandra Juhàsz
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Institute of Medical Microbiology, Semmelweis University, Budapest, Hungary
| | - Sam Jones
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Ffion Doull
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - James E. LaCourse
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Bright Mainga
- Laboratory Department, Mangochi District Hospital, Mangochi, Malawi
- Malawi Liverpool Wellcome Trust Programme of Clinical Tropical Research, Queen Elizabeth Central Hospital, Blantyre, Malawi
| | - Peter Makaula
- Malawi Liverpool Wellcome Trust Programme of Clinical Tropical Research, Queen Elizabeth Central Hospital, Blantyre, Malawi
| | - Sekeleghe A. Kayuni
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Malawi Liverpool Wellcome Trust Programme of Clinical Tropical Research, Queen Elizabeth Central Hospital, Blantyre, Malawi
- Department of Pathology, School of Medicine and Oral Health, Kamuzu University of Health Sciences, Blantyre, Malawi
- MASM Medi Clinics Limited, Medical Aid Society of Malawi, Area 12 Medi Clinic and Head Office, Lilongwe, Malawi
| | - Janelisa Musaya
- Malawi Liverpool Wellcome Trust Programme of Clinical Tropical Research, Queen Elizabeth Central Hospital, Blantyre, Malawi
- Department of Pathology, School of Medicine and Oral Health, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - J. Russell Stothard
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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Abstract
Bovine milk is known to contain a number of peptide fractions that can affect immune function. The vast majority of immunoregulatory peptides that have been characterised are hydrolysate derivatives of major milk proteins. Recent research has also indicated that the metabolic activity of probiotic lactic acid bacteria can generate de novo immunoregulatory peptides from milk, via enzymatic degradation of parent milk protein molecules. In contrast, relatively little is known of endogenous, preformed immunoregulatory peptides in milk that may be relevant to modulating human health. The natural in vivo role of preformed and enzymatically derived peptides is likely to be one of regulation of the neonatal (bovine) gastrointestinal tract immune system, in order to modulate immune function with respect to the development of immunocompetence and avoidance of undesirable immunological responses (e.g. tolerance, and hypersensitivity to nutrients). There is scope for the further characterisation of both the origin and function of milk-derived immunoregulatory peptides, so that their potential to influence human health can be fully appraised. This review highlights our current knowledge of milk-derived immunoregulatory peptides, and outlines areas that are of relevance for further research.
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Affiliation(s)
- H S Gill
- Milk and Health Research Centre, Institute of Food, Nutrition and Human Health, Massey University, Private Bag 11222, Palmerston North, New Zealand.
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