Temporal epidemiology of microfilaraemia among migrant workers entering Kuwait

<p>Abstract</p> <p>Background</p> <p>There is paucity of published data on the microfilarial infection among migrants from endemic countries entering Kuwait. The primary objectives of this study were to use routine health surveillance data to i) to estimate the prevalence of microfilarial infection in migrant workers to Kuwait and ii) to determine the occurrence of any time trends in the proportions of microfilaria positives among these workers over the recent past.</p> <p>Methods</p> <p>Monthly aggregates of microfilaria thick slide test results obtained from routine health examinations of migrant workers conducted at the Ports and Border Health Division of Ministry of Health, Kuwait between January 1, 1992 and December 31, 2006, were available for trend analysis of these time series data.</p> <p>Results</p> <p>During the study period, the prevalence (per 100,000) of microfilaraemia positive migrant workers was 48 (1169/2449360). A third-order polynomial regression model of monthly proportions of microfilaraemic workers revealed a significant initial increase (<inline-formula><m:math name="1756-0500-1-8-i1" xmlns:m="http://www.w3.org/1998/Math/MathML"><m:semantics><m:mrow><m:msub><m:mover accent="true"><m:mi>β</m:mi><m:mo>ˆ</m:mo></m:mover><m:mn>1</m:mn></m:msub></m:mrow><m:annotation encoding="MathType-MTEF"> MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacPC6xNi=xH8viVGI8Gi=hEeeu0xXdbba9frFj0xb9qqpG0dXdb9aspeI8k8fiI+fsY=rqGqVepae9pg0db9vqaiVgFr0xfr=xfr=xc9adbaqaaeGaciGaaiaabeqaaeqabiWaaaGcbaGafqOSdiMbaKaadaWgaaWcbaGaeGymaedabeaaaaa@2EA2@</m:annotation></m:semantics></m:math></inline-formula> = 2.976 (± 0.157); <it>P </it>< 0.001), followed by a significant declining trend (<inline-formula><m:math name="1756-0500-1-8-i2" xmlns:m="http://www.w3.org/1998/Math/MathML"><m:semantics><m:mrow><m:msub><m:mover accent="true"><m:mi>β</m:mi><m:mo>ˆ</m:mo></m:mover><m:mn>2</m:mn></m:msub></m:mrow><m:annotation encoding="MathType-MTEF"> MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacPC6xNi=xH8viVGI8Gi=hEeeu0xXdbba9frFj0xb9qqpG0dXdb9aspeI8k8fiI+fsY=rqGqVepae9pg0db9vqaiVgFr0xfr=xfr=xc9adbaqaaeGaciGaaiaabeqaaeqabiWaaaGcbaGafqOSdiMbaKaadaWgaaWcbaGaeGOmaidabeaaaaa@2EA4@</m:annotation></m:semantics></m:math></inline-formula> = -0.0358 (± 0.002); <it>P </it>< 0.001) and a slight but significant upward trend (<inline-formula><m:math name="1756-0500-1-8-i3" xmlns:m="http://www.w3.org/1998/Math/MathML"><m:semantics><m:mrow><m:msub><m:mover accent="true"><m:mi>β</m:mi><m:mo>ˆ</m:mo></m:mover><m:mn>3</m:mn></m:msub></m:mrow><m:annotation encoding="MathType-MTEF"> MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacPC6xNi=xH8viVGI8Gi=hEeeu0xXdbba9frFj0xb9qqpG0dXdb9aspeI8k8fiI+fsY=rqGqVepae9pg0db9vqaiVgFr0xfr=xfr=xc9adbaqaaeGaciGaaiaabeqaaeqabiWaaaGcbaGafqOSdiMbaKaadaWgaaWcbaGaeG4mamdabeaaaaa@2EA6@</m:annotation></m:semantics></m:math></inline-formula> = 0.0001 (± < 0.001); <it>P </it>< 0.001) towards the end of study period.</p> <p>Conclusion</p> <p>This study showed a recent steady but apparently asymptotic decline in the prevalence of microfilarial infection in migrant workers from filarial endemic countries to Kuwait. This may reflect either changes in the socio-economic backgrounds of recent migrants or the effects of recently initiated mass drug administration programs carried out in the endemic countries of origin.</p

Seasonality in pulmonary tuberculosis among migrant workers entering Kuwait

<p>Abstract</p> <p>Background</p> <p>There is paucity of data on seasonal variation in pulmonary tuberculosis (TB) in developing countries contrary to recognized seasonality in the TB notification in western societies. This study examined the seasonal pattern in TB diagnosis among migrant workers from developing countries entering Kuwait.</p> <p>Methods</p> <p>Monthly aggregates of TB diagnosis results for consecutive migrants tested between January I, 1997 and December 31, 2006 were analyzed. We assessed the amplitude (<it>α</it>) of the sinusoidal oscillation and the time at which maximum (<it>θ</it>°) TB cases were detected using Edwards' test. The adequacy of the hypothesized sinusoidal curve was assessed by <it>χ</it>²goodness-of-fit test.</p> <p>Results</p> <p>During the 10 year study period, the proportion (per 100,000) of pulmonary TB cases among the migrants was 198 (4608/2328582), (95% confidence interval: 192 – 204). The adjusted mean monthly number of pulmonary TB cases was 384. Based on the observed seasonal pattern in the data, the maximum number of TB cases was expected during the last week of April (<it>θ</it>° = 112°; <it>P </it>< 0.001). The amplitude (± se) (<it>α </it>= 0.204 ± 0.04) of simple harmonic curve showed 20.4% difference from the mean to maximum TB cases. The peak to low ratio of adjusted number of TB cases was 1.51 (95% CI: 1.39 – 1.65). The <it>χ</it>²goodness-of-test revealed that there was no significant (<it>P </it>> 0.1) departure of observed frequencies from the fitted simple harmonic curve. Seasonal component explained 55% of the total variation in the proportions of TB cases (100,000) among the migrants.</p> <p>Conclusion</p> <p>This regularity of peak seasonality in TB case detection may prove useful to institute measures that warrant a better attendance of migrants. Public health authorities may consider re-allocation of resources in the period of peak seasonality to minimize the risk of <it>Mycobacterium tuberculosis </it>infection to close contacts in this and comparable settings in the region having similar influx of immigrants from high TB burden countries. Epidemiological surveillance for the TB risk in the migrants in subsequent years and required chemotherapy of detected cases may contribute in global efforts to control this public health menace.</p

Polynomial regression model fitted to deseasonalized data on the proportions of pulmonary tuberculosis cases among migrants at entry in Kuwait: 1997–2006

<p><b>Copyright information:</b></p><p>Taken from "Nonlinear pattern of pulmonary tuberculosis among migrants at entry in Kuwait: 1997–2006"</p><p>http://www.biomedcentral.com/1471-2458/8/264</p><p>BMC Public Health 2008;8():264-264.</p><p>Published online 30 Jul 2008</p><p>PMCID:PMC2527606.</p><p></p

Spectral analysis of HIV seropositivity among migrant workers entering Kuwait

<p>Abstract</p> <p>Background</p> <p>There is paucity of published data on human immunodeficiency virus (HIV) seroprevalence among migrant workers entering Middle-East particularly Kuwait. We took advantage of the routine screening of migrants for HIV infection, upon arrival in Kuwait from the areas with high HIV prevalence, to 1) estimate the HIV seroprevalence among migrant workers entering Kuwait and to 2) ascertain if any significant time trend or changes had occurred in HIV seroprevalence among these migrants over the study period.</p> <p>Methods</p> <p>The monthly aggregates of daily number of migrant workers tested and number of HIV seropositive were used to generate the monthly series of proportions of HIV seropositive (per 100,000) migrants over a period of 120 months from January 1, 1997 to December 31, 2006. We carried out spectral analysis of these time series data on monthly proportions (per 100,000) of HIV seropositive migrants.</p> <p>Results</p> <p>Overall HIV seroprevalence (per 100,000) among the migrants was 21 (494/2328582) (95% CI: 19 -23), ranging from 11 (95% CI: 8 – 16) in 2003 to 31 (95% CI: 24 -41) in 1998. There was no discernable pattern in the year-specific proportions of HIV seropositive migrants up to 2003; in subsequent years there was a slight but consistent increase in the proportions of HIV seropositive migrants. However, the Mann-Kendall test showed non-significant (<it>P </it>= 0.741) trend in de-seasonalized data series of proportions of HIV seropositive migrants. The spectral density had a statistically significant (<it>P </it>= 0.03) peak located at a frequency (radians) 2.4, which corresponds to a regular cycle of three-month duration in this study. Auto-correlation function did not show any significant seasonality (correlation coefficient at lag 12 = – 0.025, <it>P </it>= 0.575).</p> <p>Conclusion</p> <p>During the study period, overall a low HIV seroprevalence (0.021%) was recorded. Towards the end of the study, a slight but non-significant upward trend in the proportions of HIV seropositive migrants was recorded. A significant rhythmic cycle of three-month duration was observed in the proportions of HIV seropositive migrants. The underlying factors for a consistent upward trend towards the end of study period and for a significant quarterly cycle in the proportions of HIV seropositive migrants merit further investigations.</p

Nonlinear pattern of pulmonary tuberculosis among migrants at entry in Kuwait: 1997–2006

<p>Abstract</p> <p>Background</p> <p>There is a paucity of published data on the pattern of pulmonary tuberculosis among migrant workers entering Middle Eastern countries particularly Kuwait. The objectives of this study were to use routine health surveillance data i) to estimate the prevalence of pulmonary tuberculosis among migrant workers at entry in Kuwait and ii) to determine the occurrence of any time trends in the proportions of pulmonary tuberculosis positive workers over the study period.</p> <p>Methods</p> <p>The monthly aggregates of daily number of migrants tested and the number of pulmonary tuberculosis cases detected during routine health examinations of migrant workers from tuberculosis high-prevalence countries were used to generate the monthly series of proportions (per 100,000) of pulmonary tuberculosis cases over 120 months between January 1, 1997 and December 31, 2006 and analysed using time series methods.</p> <p>Results</p> <p>The overall prevalence (per 100,000) of documented pulmonary tuberculosis cases among screened migrants was 198 (4608/2328582). Year-specific prevalence (per 100,000) of tuberculosis cases consistently declined from 456 (95% CI: 424 – 490) in 1997 to 124 (95% CI: 110 – 140) in 2002 before showing a steady increase up to 183 (95% CI: 169–197) in 2006. The second-order polynomial regression model revealed significant (<it>P </it>< 0.001) initial decline, followed by a significant (<it>P </it>< 0.001) increasing trend thereafter in monthly proportions of tuberculosis cases among migrant workers.</p> <p>Conclusion</p> <p>The proportions of documented tuberculosis cases among migrant workers showed a significant nonlinear pattern, with an initial decline followed by a significant increasing trend towards the end of the study period. These findings underscore the need to maintain the current policy of migrants' screening for tuberculosis at entry. The public health authorities in Kuwait and perhaps other countries in the region may consider complementing the current screening protocol with interferon-<it>γ </it>assays to detect migrants with latent <it>Mycobacterium tuberculosis </it>infection. An appropriate curative or preventive chemotherapy of detected tuberculosis cases may help in further minimizing the risk of local transmission of <it>M. tuberculosis</it>, while contributing in global efforts to control this public health menace.</p