Climate change and international trade can have important influences on the spread of infectious animal diseases and epidemics, according to a new report presented to the 87th general session of the World Organization for Animal Health (OIE) meeting May 26-31 in Paris, France.

OIE noted that the evolution of land use practices and human population distribution are closely related to these factors. For example, climatic effects — such as the El Nino phenomenon or heavy rains — influence the distribution of mosquitoes and ticks that, in turn, play roles in the transmission of vector-borne diseases, OIE said.

Furthermore, expanding trade of animals and animal products due to globalization continues to provide risk pathways for the introduction of animal diseases into new territories, the international organization said.

The conclusions of the annual OIE report on the global animal health situation were based on information reported through the World Animal Health Information System (WAHIS) by 191 countries and territories between January 2018 and March 2019. The OIE report also provides recommendations to help countries better anticipate potential threats, according to an announcement.

Climate change can have an impact on the spread of vector-borne diseases in animals and affect animal movements, such as wild bird migrations and seasonal livestock grazing patterns. OIE pointed to three vector-borne diseases that had a high impact on animal health in 2018 and recommended the following measures to tackle them:

1. Step up the surveillance and preparedness in high-risk areas during high-risk periods according to the epidemiology of the different diseases, in collaboration with public health authorities. In this regard, OIE closely works with U.N. Food & Agriculture Organization and World Health Organization through the Global Early Warning System to coordinate intelligence on outbreaks at the human/animal interface.

2. Continuously report new outbreaks through WAHIS to allow the implementation of awareness and prevention efforts.

The three vector-borne diseases OIE spotlighted include Rift Valley fever, bluetongue and West Nile fever.

OIE said 9% of countries (out of 192 reporting countries and territories) in East Africa as well as in several European countries reported an increased number of Rift Valley fever outbreaks, including human cases. This important zoonosis, transmitted through mosquitoes, causes severe diseases in ruminants and people.

Bluetongue continues to raise global interest, given its accelerated spread in recent years and its potential for further spread in the future, OIE said. Since 1998, the disease has been found outside of its traditional geographical location and is now present in almost one-quarter of reporting countries and territories from nearly all regions, OIE said.

Another challenge for veterinary and public health services is West Nile fever, which circulates through a complex cycle that involves mosquitoes and birds while affecting the health of people and horses. Its presence was reported in 14% of the 191 reporting countries and territories from four continents, with half located in Europe. The disease is seasonal, with a peak between June and November.

International trade

According to OIE, international trade is known to create risks for the propagation of animal diseases. To manage this risk, OIE said it is essential that countries implement its international standards for trade of animals and animal products, including those related to national risk management such as farm-level biosecurity, early-warning surveillance systems and contingency planning.

International collaboration and the reporting of outbreaks through WAHIS are also essential to enable countries to implement effective surveillance and control measures and to reach a better understanding of the global situation, OIE said.

The full report is available from OIE.