Persistent diarrhea is an episode of diarrhea of presumed infectious etiology, which starts acutely but lasts for more than 14 days, and excludes chronic diarrheal disorders (1). In practice this usually means having loose or watery stools more than 3 times a day, with a deviation from the previous regular stool pattern. (2). The World Health Organization (WHO) defines diarrhoea as the passing of three or more loose stools (which take the shape of the container) within a 24 hour period. Looking at the epidemiology, WHO estimates that persistent diarrhea accounts for only 10 percent of diarrheal episodes. The incidence of persistent diarrhoea was 6.3 per 100 child-years among those aged under 6 years. The peak incidence of persistent diarrhoea occurred during the first year of life, particularly among children aged 3-6 months. (3) Persistent diarrhea is both a cause and consequence of malnutrition (4). The risk of a diarrheal episode becoming persistent is manifold in malnourished children and is usually associated with secondary carbohydrate malabsorption. (5) PD occurs more frequently in very young children, in settings with poor hygiene and sanitation, or irrational usage of antibiotics, early introduction of animal milk or lack of breastfeeding (6). Inflammation and defective mucosal repair impair nutrient absorption and intestinal healing, changes are worsened by micronutrient (Eg- zinc) deficiencies (7,8). Persistent Diarrhea is being increasingly recognized as a manifestation of AIDS with up to half of HIV-infected children presenting with persistent diarrhea at admission (9-11). Infectious Enteric infections are by far the most frequent cause of persistent or chronic diarrhea, both in developing and industrialized countries. (12). Across developing countries, rotavirus and Escherichia coli are the leading causes of childhood diarrhoea. (13) Seasonal variation is noted in cases of persistent diarrhea. Seasonality provides a clue to implicate specific pathogens, although patterns may differ in tropical and temperate climates. Rotavirus and Norovirus peak in cool seasons, while enteric adenovirus infections occur throughout the year, with some increase in summer. Salmonella, Shigella, and Campylobacter favour warm weather. (14)

Observational study of 142 cases admitted with persistent diarrhea under 6 years between July 2024 and June 2026 was carried out. Clinical and demographic data were collected and analyzed Stool samples were collected within 24 hours of hospital admission and prior to starting IV or oral antibiotics. Stool specimens were tested by multiplex PCR panels capable of detecting viral, bacterial, and parasitic enteric pathogens. Monthly case counts across two years were aggregated to examine seasonal trends. Study design and setting: This single‑center prospective observational study included consecutive children aged 0–6 years admitted with persistent diarrhea between July 2024 and June 2026 at a tertiary pediatric center in Eastern India. Case definition and inclusion criteria: Children older than 6 years, children with chronic diarrhea (long-standing, non-acute onset) and children with acute gastroenteritis (episodes lasting <14 days) were excluded. Exclusion criteria: Children older than 6 years and those with chronic diarrhea or acute gastroenteritis lasting less than 14 days were excluded from the study. Laboratory methods: Real-time multiplex PCR was performed in all cases to identify the pathogen. The RevoDx Gastro Pathogen Detection Kit was used for qualitative detection of DNA/RNA from gastrointestinal pathogens. The targeted organisms in this kit were Campylobacter spp. (C.jejuni, C upsaliensis, C coli) Salmonella spp, Yersinia enterocolitica, Clostridium difficile toxin A/B, Vibrio vulnificus, Vibrio parahaemolyticus, Helicobacter pylori, Vibrio cholerae, Plesiomonas shigelloides, Enterotoxigenic Escherichia coli (ETEC), Shiga toxin producing E.coli(STEC), Shiga toxin producing E.coli (STEC) O157: H7, Enteroaggregative Escherichia coli (EAEC), Enteroinvasive Escherichia coli (EIIEC)/Shigella, Enteropathogenic Escherichia coli (EPEC), Giardia lamblia, Entamoeba histolytica, Cryptosporidium spp., Norovirus genogroup I & I, Cyclospora cayetanensis, Rotavirus A, Sapovirus (I/ II/ IV/ V), Astrovirus, Adenovirus( F40 /41). Pathogen identification was recorded as present/absent and counts were tabulated.

Table 1. Demographic and Clinical Profile Variable Category Cases (n = 142) Percentage (%) Age Group (years) 0–1 55 38.7 1–2 33 23.2 2–3 22 15.5 3–4 16 11.3 4–6 13 9.1 Sex Male 83 58.4 Female 59 41.6 Clinical Features Fever 23 16.2 Vomiting 18 12.7 Abdominal pain 68 47.9 Dehydration 76 53.5 Duration of Diarrhea 2–3 weeks 123 86.6 >3 weeks 19 13.4 Stool Characteristics Blood in stools 12 8.5 Watery stools 27 19.0 In this cohort of 142 children with persistent diarrhea, the majority were under one year of age (55 cases), with risk declining progressively in older groups. Males (83) slightly outnumbered females (59). Common clinical features included abdominal pain (68 cases) and dehydration (76), while fever (23) and vomiting (18) were less frequent. Most episodes lasted 2–3 weeks (123 cases), with 19 extending beyond three weeks. Blood in stools was noted in 12 children, and watery stools in 27. Microbiological Distribution A causative organism was identified in 135/142 (95.1%) cases. Among pathogen‑positive cases (n = 135), bacterial pathogens accounted for 84 (62.2%), viral pathogens for 56 (41.5%), and parasitic pathogens for 10 (7.4%). The most frequent individual pathogens were enteroinvasive E. coli (EIEC) 36 (25.7% of pathogen‑positive), rotavirus 24 (17.8%), and Campylobacter spp. 18 (13.3%). Seasonal variation Monthly aggregated totals (sum of both years) were computed as follows: April had the highest aggregated case count (22), followed by July and August (17 each), and May (15). January shows winter surge of such cases with 15 case count. The aggregated monthly distribution shows a clear premonsoon peak (April–May) and secondary increases in July–August and January. A bimodal pattern is evident with a prominent pre‑monsoon peak (April–May) continuing into monsoon in mid‑year (July–August) and another peak in winter (January).

Demography of Persistent Diarrhea: The highest incidence was in infants (38.7%) and over three-fourths (77.4%) of the cases were seen in children younger than 3 years. The incidence clearly declines as children age. Their immune systems mature and their exposure to diverse pathogens increases, typically leading to shorter, self-limiting acute episodes. Microbiological Spectrum: Our findings align with regional reports that document a substantial bacterial contribution to persistent diarrheal illness in children as by Moharana et al, Mathai et al. and the PGHN review emphasize the mixed viral and bacterial etiology of chronic and persistent diarrhea; our data reinforce that bacterial enteropathogens, particularly invasive E. coli pathotypes and Campylobacter, are major contributors in this setting (13,15,16). Viral agents, especially rotavirus, remain significant further highlighting the need for rotavirus vaccination. The systematic review by Abba et al. highlighted heterogeneity across LMICs (4); our study adds contemporary molecularly confirmed data from Eastern India. Seasonality: Peaks in April–May align with rising temperatures and water contamination risks; January peaks may reflect winter viral transmission. Both our data and those from the studies by McAuliffe et al and Bhan et al indicate that persistent episodes of diarrhoea are not restricted to a particular season of the year. Such a pattern is consistent with the observed association of several different pathogens with persistent episodes of diarrhoea (3,17). The study by Bhan et al is similar in pre-monsoon, monsoon and winter peaks of cases of persistent diarrhea. Premonsoon rises may reflect increasing ambient temperatures, changes in water availability and quality, and foodhandling practices that favor bacterial proliferation. Winter increases (January) may reflect viral transmission dynamics. Prevention: Promotion of Exclusive Breastfeeding and Vitamin A, Rotavirus Immunization, Improved Water and Sanitary Facilities and Promotion of Personal and Domestic Hygiene Preventive Strategies Improvements in nutritional status of infants and children as well as prevention and rational management of acute diarrhea are keys to prevention of PD. Cost effective interventions in the community include promotion of exclusive breastfeeding, safe complementary feeding practices, promotion of safe drinking water, low osmolality ORS, zinc supplementation, avoiding unnecessary antibiotics and continued feeding during diarrhea (15) Management: There is no evidence that any particular pathogen or type of pathogen is associated with persistent diarrhoea in children under the age of six in low and middle income countries seen in a study by Abba et al which is consistent with the result of our study showcasing varied infectious etiological agents of persistent diarrhea. There is therefore no evidence to justify routine antimicrobial use for children with persistent diarrhoea of unknown cause, in keeping with current guidelines. (4)

Persistent diarrhea in Eastern India is largely bacterial followed by viral in etiology, with notable seasonal clustering. Strengthening diagnostic capacity and preventive strategies (safe water, vaccination, hygiene) are essential to reduce the considerable burden it has on young population

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