The World Health Organisation has issued an alert over four cough syrups linked to dozens of deaths among children in Gambia, saying they are suspected of being contaminated and may have been distributed to other countries.

The four products – Promethazine Oral Solution, Kofexmalin Baby Cough Syrup, Makoff Baby Cough Syrup and Magrip N Cold Syrup – are all manufactured by Indian drugmaker Maiden Pharmaceuticals, which the WHO says "has not provided guarantees…on the safety and quality of these products."

The syrups have been "potentially linked with acute kidney injuries and 66 deaths among children," according to the agency , which says samples suggest they have been contaminated with "unacceptable amounts of diethylene glycol and ethylene glycol."

DEG and ethylene glycol can be found as contaminants of glycerin, an excipient widely used in oral liquid medicines, and in some cases they are thought to have been deliberately added to glycerin to bulk it out and save money.

Medicinal syrups laced with DEG – a colourless and odourless liquid with a sweet taste – have caused hundreds of fatalities over the decades, usually as a result of acute kidney failure.

Other mass poisonings linked to the contaminant occurred in Haiti in 1995-1996 (85 deaths), India in 1998 (33 deaths), Panama in 2006 (97 deaths) and Nigeria in 2008 (84 deaths). Meanwhile, there have been two separate incidents Bangladesh in 1990-92 and 2009, collectively leading to more than 300 fatalities.

Other symptoms of DEG and ethylene glycol poisoning include abdominal pain, vomiting, diarrhoea, inability to pass urine, headache, and altered mental state.

Last month, Gambia suspended all sales and imports of paracetamol syrup products on suspicion of involvement in child deaths, mainly in the under fives, that started to emerge in the summer. The country's health authorities has recommended that patients use tablets instead.