Confusion surrounds the number of H5N1 cases in Egypt

The most recent, cumulative World Health Organization (WHO) table of human H5N1 cases was published on March 3, 2015.[1] This table notes a total of 88 human H5N1 cases in Egypt through March 3, 2015. As I noted previously [2] the tabulation of counts based on the line list of cases published in the monthly risk summaries only totals 82 cases for Egypt in 2015 based on onset dates in reports of 2015.

To understand the confusion in the Egyptian case counts in the WHO table, it is necessary to consider the 2014 totals provided by WHO. The current WHO cumulative table reports 46 cases of H5N1 in 2014 with 31 cases from Egypt.[1] However, individual enumeration of WHO-confirmed H5N1 cases based on line lists in the monthly risk assessments shows a total of 52 H5N1 cases in 2014 (based on onset dates), with 37 of these reported from Egypt.[3] The table below identifies the distribution of WHO-confirmed H5N1 from Egypt by each of the monthly summaries for 2014 through the most recent assessment posted on March 3.[4]

Further complicating the confusion is the Regional Office Eastern Mediterranean (EMRO) of WHO. On March 21, 2015 EMRO published a table that only identifies 29 H5N1 cases from Egypt in 2014.[5] The EMRO data has a 8-case discrepancies with the line list of confirmed cases published by WHO.

In summary, Egypt experienced a total of 37 confirmed H5N1 in 2014 based on onset dates. In 2015, 82 WHO-confirmed cases with onsets dates before February 20 have occurred in Egypt. Since February 20, there have been at least 22 additional official cases from Egypt with onset dates on or after 20 February. Another 3 H5N1 cases have been also reported from Egypt but are not yet corroborated.

Until we get the numbers right for H5N1 in Egypt from 2014, we can’t correct the numbers for 2015. Based on the above discussion, through March 25, 2015 there have been 107 H5N1 cases in Egypt with symptom onset since January 1, 2015.  

1.  Cumulative number of confirmed human cases for avian influenza A(H5N1) reported to WHO, 2003-2015

2. Egypt leads the world in the number of human H5N1 cases

3. List of WHO Confirmed Cases in 2014

4. Human-Animal Interface, monthly risk assessment summaries

5. Avian influenza A (H5N1) in Egypt update, 21 March 2015

Egypt leads the world in the number of human H5N1 cases

In late December 2014, Egypt surpassed Indonesia in the number of reported A(H5N1) cases.[1] As of March 3, 2015, the World Health Organization (WHO) has confirmed a worldwide cumulative total of 784 human H5N1 cases, about 37% or 292 of these cases have been reported from Egypt (Table 1). Eighty-two of those cases from Egypt occurred in the first two months of 2015.[2] In addition, media reports suggests that another four cases have occurred since late February in Egypt and may be included in future monthly updates by WHO.[3]
 

The recent WHO report from 3 March 2015 notes “ The number of laboratory-confirmed human cases of avian influenza A(H5N1) virus infection in Egypt with onsets of illness in the months of December 2014, January and February 2015 are the highest numbers reported by any country in a single month.” To put these statistics in perspective, about 36% of all H5N1 cases reported from Egypt have occurred in the last 3 months. The graph below shows the distribution of WHO confirmed cases by ISO week number in Egypt since December 2014.

 Based on onset dates, since December 2014 there have been 105 H5N1 cases reported from Egypt. According to WHO at least 28 of these individuals have died. The fatality rate among this group is 27% to date, although only 17 of these cases have been reported in media reports to have recovered.

Besides the 82 cases from Egypt since the beginning of 2015, only one other case of H5N1 has been confirmed by WHO in 2015, a 37-year-old woman from Suzhou, Jiangsu Province in the People’s Republic of China. With 83 cases so far this year, the H5N1 case count for 2015 already exceeds the annual case count of H5N1 for the preceding seven years.[4]

While the spot light is on human H5N1 infections in Egypt, the single case from Suzhou, China is a reminder that the H5N1 influenza virus is endemic in many parts of the world and that human outbreaks of H5N1 in the size and the scope now occurring in Egypt could quickly develop elsewhere in the world.

1. Human Cases of Avian Influenza Infections in 2014

2. List of WHO Confirmed Cases from Egypt in 2015 (reported by WHO through 3 March 2015)

3.  Flutrackers’ list of media reports for H5N1 cases

4. Cumulative number of confirmed human cases of avian influenza A(H5N1) reported to WHO