Seasonality in TB notification in Nigera: Reality or myth?
Background: Seasonal fluctuations in tuberculosis (TB) notifications have been identified and reported in a number of countries. Nigeria remains one of the 22TB high-burden countries (HBCs) in the world, and the notification of TB cases in the country over the years has shown a definite pattern that...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wolters Kluwer Medknow Publications
2015-01-01
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| Series: | International Journal of Mycobacteriology |
| Subjects: | |
| Online Access: | http://www.ijmyco.org/article.asp?issn=2212-5531;year=2015;volume=4;issue=5;spage=165;epage=165;aulast=Kusimo;type=0 |
| Summary: | Background: Seasonal fluctuations in tuberculosis (TB) notifications have been identified and reported in a number of countries. Nigeria remains one of the 22TB high-burden countries (HBCs) in the world, and the notification of TB cases in the country over the years has shown a definite pattern that suggests seasonal variation. Previous studies conducted in India, Japan, Mongolia, the Netherlands, Russia, Spain, the United Kingdom and the United States have evaluated the seasonality of TB notification. However, in Nigeria, there has been no systematic study to establish that this pattern is not just a myth. This study seeks to establish the seasonal variations suggested by the trend pattern of TB case notification (all forms of TB) in Nigeria over the past ten years.
Method: The yearly TB notification data in Nigeria from 2004 to 2013 was examined for seasonal fluctuations by plotting the quarterly notification figures for the years under review. A rapid trend analysis was done based on the amplitude of the fluctuating curves. Standardization was done by zones.
Results: The trend analysis showed a spike in the first quarter of the year for the ten-year period studied (with the exception of 2005 and 2011). This quarter is generally characterized by the dusty, dry harmattan wind in most parts of the country, particularly the northern region. The curves generally plummeted in the third quarter and remained in that neighborhood for the rest of the year. The differences in case notification between the first and last quarter for the ten-year period ranged from 347 to 4230 cases notified. The result of this trend analysis when standardized by zones for the six zones of the country was similar to the overall result for the country.
Conclusion: According to the results of this study, there is evidence to suggest that there are seasonal variations in notification of TB cases across the four quarters of the year. This has significant implications for TB control strategies. Further investigation of the reasons for seasonal variations may help to identify risk factors. Also, planning and forecast of TB commodities to order cannot be based on experience from the preceding quarters, but must rather be based on reports from the same quarter in the previous year. Allocation of resources may also have to be intensified during the peak periods in order to adequately control the disease at these periods.
Footnotes: Further investigation is required to unmask the reasons for the seasonal variations in TB notification in Nigeria. |
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| ISSN: | 2212-5531 2212-554X |