• A polio outbreak has been declared in Papua New Guinea, sparking concern about the disease's spread in a country with low vaccination rates, health officials said.

• The virus was detected in wastewater and environmental samples in the Pacific nation’s capital Port Moresby and second largest city Lae, the World Health Organization (WHO) said.

• Two children in Lae were found to have the poliovirus type 2 strain.

• Genetic testing showed the polio strain detected in Papua New Guinea was linked to one circulating in Indonesia.

• Papua New Guinea was certified as polio-free in 2000. However, immunisation rates among children are low — less than 50 per cent.

Key points on polio:

• Poliomyelitis (polio) is a highly infectious viral disease that largely affects children under five  years of age. The virus is transmitted by person-to-person spread mainly through the faecal-oral route or, less frequently, by a common vehicle (for example, contaminated water or food) and multiplies in the intestine.

• It can infect a person’s spinal cord, causing paralysis and possibly permanent disability and death.

• In 1988, the World Health Assembly adopted a resolution for the worldwide eradication of polio, marking the launch of the Global Polio Eradication Initiative, spearheaded by national governments, WHO, Rotary International, the US Centers for Disease Control and Prevention (CDC), UNICEF, and later joined by the Bill & Melinda Gates Foundation and Gavi, the Vaccine Alliance. 

• Wild poliovirus cases have decreased by over 99 per cent since 1988, from an estimated 350,000 cases in more than 125 endemic countries then to 175 reported cases in 2019. 

• Of the three strains of wild poliovirus (type 1, type 2 and type 3), wild poliovirus type 2 was eradicated in 1999 and no case of wild poliovirus type 3 has been found since the last reported case in Nigeria in November 2012. Both strains have officially been certified as globally eradicated. At present, wild poliovirus type 1 affects two countries —  Pakistan and Afghanistan.

• Economic modelling has found that the eradication of polio would save at least $40–50 billion, mostly in low-income countries.

• There are two vaccines available: oral polio vaccine and inactivated polio vaccine. 

• Both are effective and safe, and both are used in different combinations worldwide, depending on local epidemiological and programmatic circumstances, to ensure the best possible protection to populations can be provided.

Eradication of polio in India

• India was certified polio-free by the Regional Polio Certification Commission in 2014. 

• Last case of wild poliovirus in the country was reported in 2011 from Howrah, West Bengal and no wild poliovirus cases have been reported thereafter from any state/UT.

(The author is a trainer for Civil Services aspirants.)