Highly pathogenic avian influenza A(H5N1) has ravaged the Egyptian poultry population. Ninety human cases, including 27 fatalities have been recorded by 30 December, 2009. However, epidemiological information on the infection in humans in Egypt is scarce. We analysed the first three years of highly pathogenic avian influenza A(H5N1) in Egypt between 20 March 2006 and 31 August 2009 and found that more cases occurred in females than males, especially in 2006 and 2007. Women in the age group 20-39 years had the greatest tendency to be infected. It took an average of one day and 18 hours to seek medical assistance in patients who recovered and of six days in fatal cases. Children sought treatment much earlier than adults. On average, patients died 11 days after the onset of symptoms. Exposure to infected poultry remained the most important risk factor.
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Introduction
On 17 February 2006, highly pathogenic avian influenza A(H5N1) was first reported in the poultry population in Egypt [1]. Since that time, the infection had affected at least 21 governorates forcing over 1.5 million individuals to loose their source of livelihood [1]. Overall, 370 backyard poultry flocks, 850 farms, and four zoos have been affected, and more than 36 million birds (mainly chickens) have died or have been culled in Egypt at an enormous cost to the country [1]. Currently, the virus is endemic in the Egyptian poultry population.
The first human case of avian influenza A(H5N1) in Egypt occurred on 17 March 2006 [2], and to date (30 December 2009), the statistics of human infection and fatalities continue to rise. Specifically, 90 human cases (approximately one fifth of the total global count), including 27 fatalities (approximately one eleventh of the global count) have been recorded in Egypt as of 30 December 2009 [2]. These numbers rank Egypt third in the list of recorded human cases and fatalities in the world, after Indonesia and Vietnam, and remain by far the highest in Africa. The World Health Organization (WHO) had previously stated that “countries around the world had improved their defenses against bird flu, but the situation remained critical in Egypt and Indonesia where the risk of the H5N1 virus mutating into a major human threat remains high” [3].
Worrisome with the situation in Egypt is the frequency with which women and young people are being infected and the very current trend of rising infections in children: in 2009 alone, 79% of all infected individuals were under 10 years old. Between January and December 2009, 17 of the 34 recorded cases involved children between 12 and 30 months-old. Similarly, at the time of this report, human cases of 2009 pandemic influenza A(H1N1) had also been confirmed in the Egyptian population, which raises the possibility of co-infection and the emergence of reassortant viruses.
While the situation in Egypt remains critical, empirical evaluation of its peculiarities seem to be lacking, except for a very recent report by Dudley [4]. Assessment of the scientific literature and epidemiological data returned little or no concrete evidence from Egypt. However, the country has provided adequate records to international organisations like the WHO and the World Organization for Animal Health (OIE) and these reports have improved significantly since the first submission in terms of spatial and temporal data, and clinical records of affected persons.
In this study, we analysed the records on avian influenza A(H5N1) in Egypt between 20 March 2006 and 31 August 2009 and explain the epidemiological significance of our findings.
Materials and Method
The Egyptian government reports to the WHO, available on the WHO website [2], were the primary source of data for these analyses. We considered all laboratory-confirmed human cases of avian influenza A(H5N1) reported to the WHO from Egypt between 20 March 2006 and 31 August 2009. All positive samples reported and used in these analyses had earlier been confirmed by microneutralisation assay on serum or by PCR on respiratory tract specimens as reported [5]. Similar confirmatory tests were done in the Egyptian national reference laboratory and at the WHO reference laboratories for diagnosis of influenza A(H5) infection, including the United States Naval Medical Research Unit 3 in Cairo, Egypt [4].
The parameters included in our analysis were: date of exposure, date of onset, course of symptoms, and time from hospitalisation until death/recovery, as listed in the WHO situation reports on avian influenza [6].
In the absence of complete information, reports were based on approximate dates and times from the reports. However, in cases of ambiguity arising from the records, such data were excluded from the calculations. In total, 85 confirmed cases were reported during the study period, of which 27 were fatal. After the exclusion of ambiguous data, only 63 of the 85 reported cases and 20 of the 27 fatal cases were evaluated for symptoms and hospitalization; and 44 of the 58 cases who recovered or were stable were analysed for symptoms and recovery. Analyses were performed using StatGraphics v2.0. Distributions were compared using chi-square test, and medians were compared using Fisher’s exact test.
Results
Demographic characteristics
In the period under analyses, 85 cases were evaluated, 32 of whom were male and 53 were female. Eighteen cases had been reported in 2006, 25 in 2007, eight in 2008 and 34 to date (31 August) in 2009, including a total of 27 human fatalities over the three and a half-year period.
The youngest cases were one year of age (two boys), and the oldest case was a 75 year-old woman. The median age of all confirmed cases was six years. The age of the cases (n=85) ranged from 12 months to 75 years, with a mean of 13 years and two months. The median age of all fatalities (n=27) was 25 years (range: four to 75 years) and the mean was 26 years and three months. The median age of the female cases (n=53) was 15 years, (range: 14 months to 75 years) and the mean was 16 years and 10 months, while the median age of the male cases (n=32) was four years (range: two months to 32 years) and the mean seven years and two months (Table, Figures 1 and 2).
Table. Human cases and fatalities associated with avian influenza A(H5N1) in Egypt, 20 March 2006–31 August 2009 (n=85)
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