Influenza monthly update, April 2018

In the WHO Eastern Mediterranean Region, influenza activity continue to decrease in the month of April 2018 in many countries reporting data to FluNet and EMFLU namely, Afghanistan, Bahrain, Egypt, Iran (Islamic Republic of), Iraq, Jordan, Kuwait, Lebanon, Morocco, occupied Palestinian territory, Oman, Pakistan, Qatar, Saudi Arabia, Syrian Arab Republic and Tunisia (Fig. 1).

April_influenza_map_2018

Fig. 1. Influenza geographic spread in the Eastern Mediterranean Region, April 2018

Influenza activity by subtype

  • In April 2018, no new cases of human influenza A(H5N1) were reported in Egypt.
  • In the northern Africa influenza transmission zone, Tunisia reported sporadic circulation of A(H1N1)pdm09 and influenza B, while Egypt reported co-circulation of all seasonal influenza viruses.
  • In the Western Asia influenza transmission zone, influenza A(H1N1)pdm09 was detected with influenza B virus in Bahrain, Kuwait, Lebanon, Oman, Qatar and Saudi Arabia, while Jordan reported A(H1N1)pdm09 and influenza B, Iraq reported circulation of A(H1N1)pdm09, while oPt reported circulation of influenza A(H1N1)pdm09 and A (H3N2). 
  • In southern Asia transmission zone, Afghanistan reported sporadic circulation of influenza B; Iran (Islamic Republic of) reported sporadic detection of seasonal influenza A, and Pakistan reported co-circulation of all seasonal influenza viruses.

Source of transmission zones

Fig. 2 shows the weekly distribution of influenza subtypes.

Fig._2

Source: FluNet and EMFLU

Fig.2. Weekly positive cases of influenza by subtype, Epi week 17/2017–2018

Circulating influenza viruses by subtype 

During April 2018, national influenza centres and influenza laboratories in the Region tested a total of 4818 specimens for influenza viruses of which 747 tested positive (16%).

The average percentage of positivity rates is 16%, with highest positivity rate recorded in Bahrain, Egypt, Lebanon, Kuwait and Qatar.

Of the viruses tested, 511 (68%) were influenza A viruses, including 371 (50%) influenza A/H1N1pdm09 virus and 109 (15%) were influenza A/H3 virus. Influenza B virus accounted for 235 (31%) including 221 (29%) influenza B (lineage not determined) and 14 (2%) B (Yamagata lineage) (Fig. 3).

Fig._3

Fig. 3. Circulating influenza viruses in the Region by subtype, Epi week 14-17, 2018

Related link

Influenza monthly update, April 2018 [pdf]