GBS Outbreak in Pune: Lessons Learnt

GBS Outbreak in Pune: Lessons LearntGuillain-Barr syndrome (GBS) is a rare neurological disorder that affects the peripheral nervous system, causes sudden numbness and muscle weakness.GBS occurs worldwide with an overall incidence rate of 1-2 cases per 100,000 people per year, affecting all age-groups, but is slightly more common in males than in females.Mortality, or severe disability due to GBS, occurs in around 20% of patients.As of February 2025, 140 cases and four deaths due to Guillain-Barr syndrome have been reported in Pune.The outbreak has shocked the public-most people have never heard of this rare, autoimmune neurological disorder before.Guillain-Barr syndrome leads to the immune system attacking the peripheral nervous system, causing weakness in the muscles, and in some cases, paralysis.But how did a rare condition show up in so many people at the same time?What could be behind the large number of cases?What could be done to prevent future outbreaks?These are the few questions that need answers.At present, the outbreak could be linked to a bacterial infection that many of the patients contracted prior to showing symptoms.The debilitating neurological disorder, GBS, could be considered one of the largest GBS outbreaks as medical literature classified 30-50 cases as an outbreak until 2019 when Peru registered the worst flare-up.The South American country had 1,120 cases in 2019, with 683 cases reported in two months.The country's annual caseload stood at 59 in 2017 and rose to 262 in 2018 before peaking in 2019.Unlike India, where the present outbreak seems confined to only Pune, Peru registered cases from across the country and had little information available about deaths.The Peruvian story didn't end there; the country witnessed an outbreak again in 2023 when 130 suspected cases were reported between June 10 and July 15.The problem with GBS is that it is an autoimmune condition that technically does not seem like an epidemic-causing condition.GBS has been seen as an independent disorder that is sporadically seen across the country, but now we have seen that it can emerge as an outbreak and study it epidemiologically to look for links between the various pathogens.The Pune health authorities are testing water samples in all the areas where the outbreak has been reported.The outbreak was linked to contaminated water sources and a bacterial infection.We need to study the common factors between the patients to understand why GBS has emerged as an outbreak.The only common link between Peru and Pune is the microbe-Campylobacter jejuni.Smaller studies from across the world have shown that Campylobacter jejuni infection is linked with higher disability and mortality rates.GBS has been so rare-India has a reported annual incidence of 1.75 -2 per 1 lakh population-that there are few in-depth studies.The first-ever detailed analysis of the prevalence and disability burden of GBS was conducted in 2021 and appeared in the 'Journal of Neuroinflammation'.Using data between 1990 and 2019 from the Global Burden of Diseases Study 2019, the analysis showed that Japan, Brunei Darussalam, Singapore, the Republic of Korea, the US, and Mexico had much higher than expected burdens, whereas countries and territories such as China, Fiji, Taiwan, and Guam had much lower than expected burdens.The highest prevalence rate of GBS was found in Japan, probably due to the high frequency of infections and presumably also due to genetic and environmental predispositions.It said higher exposure to potential causes, such as the microbes Haemophilus influenzae, Cytomegalovirus, Zika virus, and respiratory or gastrointestinal infections, could be another reason for the increase.The outbreak in Pune is being traced to a pathogen, Campylobacter jejuni, a leading cause of foodborne infections, and the biggest driver of GBS worldwide.The link between the two was discovered in the 1990s in rural China, where the pathogen was common in chickens, and GBS outbreaks occurred every monsoon as children played in water contaminated by chicken or duck droppings.Did chlorination lapses lead to GBS in people? is another question that is frequently asked.Civic health authorities in Pune are investigating whether lapses in water chlorination in wells contributed to a rise in GBS cases.Many patients had diarrhea before developing GBS symptoms.The affected wells, supplying water to both municipal and private tankers, are under scrutiny.Experts suggest even a temporary drop in chlorine levels could lead to bacterial contamination.After the surge in GBS cases, authorities carried out 'superchlorination' of wells, which may explain the absence of the Campylobacter jejuni bacteria in later water tests by the National Institute of Virology (NIV).The NIV confirmed contaminated water as the main cause of the spikes in GBS (GBS) in parts of Pune.Under the Integrated Disease Surveillance Programme, the Public Health Department has so far collected 3,868 water samples from different parts of the city and sent them to the public health laboratory for chemical and biological analysis.Among the samples, 37 water sources were found contaminated.A total of 80 serum samples have been sent to NIMHANS, Bengaluru, for antiganglioside antibodies testing.The World Health Organization (WHO) is supporting health authorities to respond to suspected and confirmed cases of GBS in Pune.WHO teams are on the ground training the health workforce in conducting 'active case searches' in the community living in the affected areas to ensure every suspected case is identified, diagnosed and treated.Working closely with Pune Municipal Corporation and state and district authorities to trace and test suspected cases and follow up on confirmed cases, WHO medical officers are also assisting health authorities analyze epidemiology and trends.This includes preparation of a 'spot map' to show the geographical distribution of disease, and creation of an 'epidemic curve' of suspected cases to identify the distribution of new cases over time to support epidemic investigation.WHO teams are also conducting field work to validate household visits, monitoring the response conducted by central, state, district/corporation health officials, and participating in the state-, district-and corporation-level reviews.WHO is providing technical and on-ground field support to district-and state-level teams to empower responders with adequate resources, training, and support systems.