Epidemiology and Genetic Characterization of H3N8 Equine Influenza Virus Responsible for Clinical Disease in Algeria in 2011.

This research article talks about an outbreak of the H3N8 Equine Influenza Virus in Algeria in 2011. The virus affected different age groups of horses differently and was found to be similar to strains circulating in the European horse population during the same period.

Understanding the H3N8 Equine Influenza Virus Outbreak

This study investigates an equine influenza outbreak that occurred in Algeria in 2011. The outbreak originally started in the Tiaret province, eventually spreading to other parts of the country. Almost 900 horses across many provinces were affected. The research included a detailed study of 325 affected horses from various age groups, aiming to understand the expression of the virus.

• The expression of clinical signs was found to be age-dependent. Horses under 15 months old experienced a morbidity rate of 14.9%, whereas older horses (over 8 years old) had a lower rate of 4.95%.
• Interestingly, the morbidity rate saw a substantial increase in horses aged between 18 months and 7 years, rising to 100%.

Detection and Characterization of the Virus

To understand the nature and origin of the virus, researchers conducted detailed study on nasopharyngeal swabs taken from non-vaccinated horses.

• The H3N8 virus was detected using a qRT-PCR, a method capable of detecting a small portion of the gene encoding the matrix protein (M) in the virus.
• The virus isolates were identified specifically as H3N8 by sequencing the haemagglutinin (HA) and neuraminidase (NA) genes of the virus.
• The virus was named from A/equine/Tiaret/1/2011 to A/equine/Tiaret/10/2011 to distinguish it from others.

Virus Comparison & Conclusions

Comparison of the Algerian strains with other strains helped researchers understand its ancestry and spread.

• Alignment of the HA1 amino acid sequence confirmed that the viruses are part of the Florida Clade 2 sublineage in the American lineage, suggesting their origin.
• The Algerian strains were found to be closely related to those in circulation in Yokohama, Eyragues, Bokel, and Lichtenfeld during 2010 to 2012, indicating a potential common source or infection pathway.
• The close relation to the European horse population confirms that this strain was also prevalent in Europe in 2010, 2011, and 2012.