INTERVIEW | A Comprehensive Case Investigation Could Reveal the True Cause of the GBS Outbreak: Dr Pradeep Awate

What is GBS?

Guillain-Barré Syndrome (GBS) is an autoimmune disease where the patient’s immune system attacks the nervous system, causing multiple dysfunctions from toe to face. Unlike COVID-19, which spreads through human contact, GBS is not communicable. It develops following a bacterial infection, making standard communicable disease protocols less relevant.

How does GBS spread?

Bacterial or viral infections, from fever to gastroenteritis, are primary triggers for GBS. In some cases, surgery or vaccination may precede GBS symptoms by three to four weeks. However, causes vary case by case.

Given the multiple possible causes, what is the proportion of GBS cases?

GBS is quite rare in normal statistics. The incidence rate is one to two cases per 1,00,000 population annually. For example, in Maharashtra, with its population of 140 million, 2,800 GBS cases per year would be considered normal. While GBS cases occurred previously, they were typically spread throughout the year. Pune’s sudden surge makes this outbreak particularly concerning and warrants thorough investigation.

You mentioned viral infections can cause GBS. Which viruses or bacteria are potential triggers?

Several bacteria and viruses can trigger GBS. In Pune’s outbreak, four cases were linked to Campylobacter jejuni (commonly called C-jejuni), which typically causes 30 per cent of all GBS cases. This bacteria, found in poultry and cattle, spread through contaminated food or water. Infected individuals experience diarrhoea, abdominal cramps, stomach pain, and vomiting. GBS typically develops three to four weeks after infection, though the incidence remains at one to two cases per 1,00,000 people. Other triggers include Zika virus, dengue, COVID-19, and in some cases, vaccination.

Are there documented cases of vaccination-induced GBS?

Yes. During the 1976 influenza vaccination campaign, some GBS cases were reported. However, Pune’s current outbreak differs: four patients tested positive for C-jejuni, and eleven contracted norovirus. Both infections present similar symptoms of vomiting and nausea.

There is widespread fear in Pune that diarrhoea or vomiting leads to GBS. What is your response?

People should understand that not every case of diarrhoea or vomiting develops into GBS. The outcome depends on the patient’s immune system. Doctors cannot predict which person’s immune system will attack their nervous system. To address these fears, we need to explain the scientific mechanism behind this process.

What is this scientific explanation?

We must understand why certain immune systems behave abnormally by attacking their own nervous system. Experts call this molecular mimicry: certain bacterial components resemble nerve cells, confusing the immune system into attacking these cells, which leads to nerve damage.

How does this affect nerve cells?

Nerve cells function like electric wires, transmitting messages between the brain and body parts. These nerves have a protective coating called myelin. In GBS, this myelin sheath becomes damaged or destroyed, slowing message transmission between the brain and body. In some cases, the nerve cells themselves are destroyed. This damage causes progressive symptoms: initial numbness and weakness in legs; spread to hands; difficulties with eating and walking; and possible facial paralysis. In severe cases, respiratory muscle damage requiring ventilator support.

Studies show that 10-15 per cent of GBS patients need ventilator support. While most patients recover within fifteen days to one month, 4-5 per cent may require two months to a year for full recovery.

What treatment options exist for GBS patients?

Treatment varies by case severity. Most patients with mild cases respond well to standard treatment, including immune system support and antibiotics. For the 10-15 per cent of critical cases, there are three main treatment approaches: Plasma exchange to remove antibodies. Intravenous immunoglobulin (IVIG) and ventilator support or regular monitoring of heart rate and blood pressure. These treatments are effective in 90-95 per cent of GBS cases.

Why has Pune’s outbreak become so serious?

The situation is exceptional. Looking at recent GBS history worldwide, we saw 36 cases in a northern Chinese city in 2007. Peru has experienced 700-800 cases annually from 2019 to 2023, primarily due to the Zika virus. But Pune’s sudden surge is unique. Most cases are concentrated in the city’s periphery and newly incorporated villages within the municipal corporation area.

Are you suggesting a connection to rapid urbanisation around Pune?

Yes. Symptoms like gastroenteritis, diarrhoea, and vomiting stem from contaminated food and water. Many villages face serious drinking water pollution issues. As cities expand, these villages are incorporated into municipal areas without adequate infrastructure development. This leads to frequent fever and gastroenteritis outbreaks. Poor sewage systems create multiple opportunities for water contamination. These issues require attention at both local and policy levels.

Could Pune’s recent surge in Zika cases be behind the GBS outbreak?

I cannot dismiss this possibility. The situation warrants a thorough investigation. Pune has experienced numerous Zika cases over the past year, along with dengue and gastroenteritis. The same mosquito species, Aedes aegypti (taxonomically the Aedes (Stegomyia) genus), transmits these infections. The connection between sanitation and water pollution suggests that a comprehensive case investigation could reveal the true cause of the GBS outbreak.

What precautions would you recommend to the public?

I have two key recommendations. First, don’t panic. GBS is completely curable, and most cases of diarrhoea or vomiting don’t develop into GBS. The incidence remains low. Second, take strong preventive measures: Avoid street food; boil drinking water; and choose fresh food. Cook poultry dishes at home thoroughly. These precautions will help prevent infection and strengthen your immune system.