High temperature effect on daily all-cause mortality in Tunis 2005-2007.

BACKGROUND: The relationship between thermal stress and health has been only marginally investigated in North Africa. This study aimed to estimate the short-term effect of heat on total mortality, in the city of Tunis in 2005-2007, using time series analysis. METHODS: The study period was restricted to the summer season (May-October) and heat effect was assessed using maximum temperature as exposure variable. We estimated the breakpoint above which heat-related mortality begins to increase using a segmented linear regression. A Poisson Generalized Estimating Equations (GEE) model was then used to estimate the impact of heat on daily mortality. Models were adjusted for nitrogen dioxide (NO2), trend, calendar month, day of the week, the Ramadan period, and holidays. RESULTS: The estimated breakpoint was 31.5°C (standard deviation: 0.9°C). After adjustment for potential confounders, the daily mortality increased significantly by 2.00% [95% confidence interval: 0.68-3.16] for a 1°C increase in daily maximum temperature above the breakpoint. An increase of 10mg/m3 in NO2 was associated with a significant increase in daily mortality (0.48% [0.08-0.88]). CONCLUSION: There is an important effect of heat on daily mortality in the city of Tunis. This is the first evaluation of such an association in a North African city with hot and dry summers and a lower middle economy.

Modelling of seasonal influenza and estimation of the burden in Tunisia.

The burden of influenza was estimated from surveillance data in Tunisia using epidemiological parameters of transmission with WHO classical tools and mathematical modelling. The incidence rates of influenza-associated influenza-like illness (ILI) per 100 000 were 18 735 in 2012/2013 season; 5536 in 2013/14 and 12 602 in 2014/15. The estimated proportions of influenza-associated ILI in the total outpatient load were 3.16%; 0.86% and 1.98% in the 3 seasons respectively. Distribution of influenza viruses among positive patients was: A(H3N2) 15.5%; A(H1N1)pdm2009 39.2%; and B virus 45.3% in 2014/2015 season. From the estimated numbers of symptomatic cases, we estimated that the critical proportions of the population that should be vaccinated were 15%, 4% and 10% respectively. Running the model for the different values of R0, we quantified the number of symptomatic clinical cases, the clinical attack rates, the symptomatic clinical attack rates and the number of deaths. More realistic versions of this model and improved estimates of parameters from surveillance data will strengthen the estimation of the burden of influenza.

Modelling of seasonal influenza and estimation of the burden in Tunisia

The burden of influenza was estimated from surveillance data in Tunisia using epidemiological parameters of transmission with WHO classical tools and mathematical modelling. The incidence rates of influenza-associated influenza-like illness [ILI] per 100 000 were 18 735 in 2012/2013 season; 5536 in 2013/14 and 12 602 in 2014/15. The estimated proportions of influenza-associated ILI in the total outpatient load were 3.16%; 0.86% and 1.98% in the 3 seasons respectively. Distribution of influenza viruses among positive patients was: A[H3N2] 15.5%; A[H1N1] pdm2009 39.2%; and B virus 45.3% in 2014/2015 season. From the estimated numbers of symptomatic cases, we estimated that the critical proportions of the population that should be vaccinated were 15%, 4% and 10% respectively. Running the model for the different values of R0, we quantified the number of symptomatic clinical cases, the clinical attack rates, the symptomatic clinical attack rates and the number of deaths. More realistic versions of this model and improved estimates of parameters from surveillance data will strengthen the estimation of the burden of influenza

En Tunisie, la charge de la grippe a été estimée à partir des données de surveillance, en utilisant les paramètres épidémiologiques de la transmission avec les outils classiques de l'OMS et la modélisation mathématique. Les taux d'incidence des syndromes de type grippal [STG] associés à la grippe étaient 18 735 pour 100 000 pour la saison 2012-2013 ; 5 536 pour 2013-2014 et 12 602 pour 2014-2015. La part estimée de STG associés à la grippe pour la charge totale de patients externes était respectivement de 3,16%, 0,86% et 1,98% pour les trois saisons. Parmi les patients positifs au virus de la grippe, la répartition était la suivante pour la saison 2014-2015 : 15,5% pour le virus A[H3N2] ; 39,2% pour le virus A[H1N1]pdm2009 ; et 45,3% pour le virus B. A partir du nombre estimé de cas symptomatiques, nous avons calculé que la proportion critique de la population devant être vaccinée était respectivement de 15%, 4% et 10%. L'exécution du modèle avec les différentes valeurs de R0 nous a permis de déterminer le nombre de cas cliniques symptomatiques, les taux d'attaque clinique, les taux d'attaque clinique pour les cas symptomatiques et le nombre de décès. Des versions plus réalistes de ce modèle ainsi que des estimations améliorées des paramètres issus des données de surveillance permettront d'accroître l'utilité des modèles mathématiques

[Relationship between temperature and mortality in the city of Tunis: 2005-2007]. / Relation temperature-mortalite pour la ville de Tunis: 2005-2007.

The influence of thermal stress on health is proved. In the light of the current climate change this relationship should be extensively investigated. This study aims to describe the relationship between temperature and total mortality in the city of Tunis over a period of three years, from 2005 to 2007 using time series analysis. The form of the relation (crude and adjusted) between mortality and temperatures was investigated using Poisson generalized additive models (GAM). Confounders included in the models were pollutant, trend, calendar month, day of the week, the period of Ramadan, and holidays. The adjusted relationship between mortality and temperature was "V" shaped with a steeper slope for low temperatures than for high temperatures. The impact of heat on mortality will be further analyzed to refine our findings and to contribute to the elaboration of guidelines for preventive strategies.

A case control study to assess risk factors for hepatitis C among a general population in a highly endemic area of northwest Tunisia.

A matched case-control study was undertaken in 2004 in Béja, north-western Tunisia, to evaluate potential risk factors for hepatitis C infection. Cases were anti-HCV positive subjects screened in 1996 serosurvey. HCV seronegative controls (5 per case) were selected in the proximity of cases and matched for age and gender. A standardized questionnaire was used to collect demographic, socioeconomic, social behavior, medical and surgical history information. Matched odds ratios (OR) and adjusted OR (AOR) and their 95% CI were calculated in multivariate analysis using logistic regression. 57 HCV positive cases (mean age 61.63 +/- 14,84; 68.4 % female) and 285 HCV negative controls (mean age 60.95 +/- 14.66; 68.4 % female) were enrolled. Multivariate analysis revealed that intravenous drug injections (AOR=1.96; 95%CI[1.02-3.8] p=0.045), past history of invasive procedures (AOR=2.53; 95%CI[1.21-5.29] p=0.0014) and medical history of hypertension (AOR=2.31; 95%CI [1.17-4.56]p=0.015) were significantly associated to HCV infection. These results suggest that nosocomial transmission of HCV infection in north-west Tunisia is common.

[Risk factors of leishmanin-skin test positivity in transmission of Leishmania infantum in the center of Tunisia]. / Les déterminants de la positivité au test cutané à la leishmanine dans l'aire de transmission de Leishmania infantum dans le centre tunisien.

This work aims to estimate prevalence and evaluate risk factors of leishmanin-skin test positivity. A cross-sectional leishmanin skin test study was carried out on a sample of 3190 healthy volunteers living in the gouvernorates of Kairouan and Kasserine. Age standardized prevalence of leishmanin-skin test positivity was 45.9% (CI95% = [43.9-47.9]) confirming the hyper endemicity of this region. The rate of leishmanin-skin test positivity ranged from 75.9% (CI95% = [71.9-79.5]) in Zaghdoud (Kairouan) to 6.5% (CI95% = [3.7-11.01) in Abdeladhim (Kasserine). There is no significant difference between men and women suggesting a similar exposure to infection. In the districts of Zaghdoud, Sidi Amor, El Hajeb and chbika, age specific rates showed a rapid increasing positive prevalence with age reaching a proportion exceeding 80% after the age of 15 years. However, the age specific prevalence from other delegations showed a progressive increasing trend with age, with a low rate for younger children and a plateau of 75% after 45 years. Multivariate analysis of leishmanin-skin test positivity risk factors showed that only district and age are determinants of this infection.

Investigation of the spread of human visceral leishmaniasis in central Tunisia.

The epidemiology, clinical patterns, and spatial spread of Mediterranean visceral leishmaniasis were retrospectively studied in central Tunisia. The clinical profile of the disease was typical of the Mediterranean infantile form. Malnutrition and associated infectious diseases were observed in 62.5% and 55% of cases, respectively. The case-fatality rate was 6.2% and resistance to meglumine antimonate was observed in 1.6% of patients. The annual incidence of cases increased from approximately 10 cases per year before 1991 to approximately 50 cases per year between 1992 and 1994. The cumulative incidence was 133.7/100,000 among children aged < 15 years. This increase was preceded by 3 years of high mean annual rainfall in the region. The spatial distribution of the incidence of the infection through time showed an aggregation of cases in the northern part of the area where intensive agriculture projects took place during the last 10 years, leading to the establishment of a stable Leishmania infantum transmission cycle below the Atlas mountain chains, and an evident tendency to a progressive extension to the south.