Sometimes viruses in animals acquire the potential to transfer in humans and infect them. Such type of an infection is referred to as a zoonotic infection. Many influenza viruses that cross the animal-human divide have often led towards epidemic and pandemic situations. The most common ones in this case include the avian and swine influenza viruses.
Horses, dogs, and some other animals can also sometimes transmit their influenza viruses to humans which resemble the human influenza viruses but are still distinct.
Situation in Pakistan
According to a report published by the World Health Organization in August 2017, the human disease burden for zoonotic influenza viruses in Pakistan could be assessed from the fact that an H5N1 (avian influenza) outbreak occurred in 2007 resulting in one death. The country’s first H1N1 infection (swine influenza) was registered on June 18, 2009. From 2010 to 2011 influenza incidence rate again raised from 18% (372 cases) to country’s highest outbreak with 28% (673 cases). From 2008 to 2011, about 1489 (22.8%) positive cases of influenza virus were confirmed from 6258 suspected specimens with the provincial distribution of 2% in Baluchistan, 8% in Khyber Pakhtunkhwa, 13% in Sindh, 24% in Punjab and 53% in Federal capital. Keeping up with the trend, the virus claimed many lives along the years: 444 in 2013, 28 in 2015 and 31 in 2016.
Animal disease burden was reported to be because of H7N3, H9N2, H5N1, H3N1, H4N6 and H14N3. H9N2 is considered endemic in Pakistan. Since 1995 there have been 3 highly pathogenic H7N3 outbreaks affecting poultry with mortality rates up to 80%, with the last reported outbreak in 2005. There has only been one introduction of H3N1, H4N6, and H14N3 reported in Pakistan between 2010–2012.
Vaccine and Treatment Status
Globally, vaccines for swine influenza viruses are available for both animals and humans. In Pakistan, the influenza vaccine consists of H1N1 (swine flu) and H3N2 (mutant). Two inactivated avian influenza vaccines, including adjuvanted and unadjuvanted influenza A/H5N1 vaccines, are licensed in the US. Vaccines for H5N1 and H7N9 are globally available as preventive or adjunct control measures during an outbreak. In Pakistan, H5N1/ H5N2, H9N2 and H7N3 vaccines are used.
Treatment for humans includes supportive care and antiviral agents. Some drugs such as oral oseltamivir and inhaled zanamivir have proven efficacy over placebo for treatment of uncomplicated influenza in randomized controlled trials (RCTs).
Involvement of Organizations and Livestock Sector in Disease Control
Agriculture and livestock sectors are major contributors to Pakistan’s economy. 19% of GDP from a 2016–2017 economic survey of which 11% of the contribution came from the livestock sector specifically. Sindh Poultry Vaccine Centre (SPVC) is a vaccine production unit in Pakistan that is currently working on the production of Influenza virus vaccines for poultry. National Institute of Health (NIH), Islamabad and National Agricultural Research Centre (NARC), Islamabad are also involved in planning and organizing vaccination strategies against the influenza in poultry. However, the World Health Organization states the factors that need more work in this regard. Coordination, surveillance, laboratory infrastructure, and funding are the factors as listed by WHO. Lack of intersectoral collaboration/ coordination, event based surveillance, and inadequate vet public health lab network demands action by the authorities. Also, the Avian Influenza contingency plans were created in 2005 and separately for human health and animal health. After 2010, data sharing decreased within sectors and remained uncoordinated between sectors. There is a need to revisit the current plans to improve joint coordination and sharing of data.