Desert dust episodes during pregnancy are associated with increased preterm delivery in French Guiana.

Preterm deliveries are a major multifactorial public health problem in French Guiana. Desert dust episodes have been associated with preterm delivery in Guadeloupe, a territory with similarities to French Guiana. We thus tried to replicate this finding in the context of French Guiana. A retrospective ecological cohort study combined daily PM10 concentration measurements during pregnancy and term at delivery extracted from French Guiana's computerized pregnancy delivery registry. Daily PM10 concentrations during the course of pregnancy were analyzed as mean concentrations and as the proportion of intense dust episodes (≥55 µg PM10/m3). These exposure variables were studied in relation to the outcome of preterm delivery. Overall, 3,321 pregnant women with complete daily PM10 measurements were included, of whom 374 (11.26%) delivered prematurely. Among preterm deliveries, 168 (44.9%) were spontaneous deliveries and 206 (55.1%) were induced. Rank-sum tests showed that, for spontaneous and induced spontaneous deliveries, both mean PM10 concentrations and proportions of intense desert dust episodes were significantly greater among preterm births than among term births. Although the proportion of intense desert dust episodes during pregnancy was significantly associated with spontaneous preterm deliveries, the relation was U-shaped, with an adjusted odds ratio (AOR) = 2 (95%CI = 1.2-3.1) for lowest values relative to median values and AOR = 5.4 (95%CI = 3.2-8.9) for the highest values relative to median values. Similarly, the proportion of intense desert dust episodes during pregnancy was also significantly associated with induced preterm deliveries in a U-shaped manner (AOR = 2.7 (95%CI = 1.6-4.5) for the lowest relative to median values and AOR = 6.8 (95%CI = 3.9-11.9) for the highest relative to median values). Although in our study the relation between PM10 concentrations appeared non-linear, the highest mean concentrations and intense desert dust episodes were indeed associated with both spontaneous and induced preterm delivery.

Prevalence of Hepatitis B Virus Infection among Pregnant Women Attending Antenatal Clinics in Vientiane, Laos, 2008-2014.

The Lao People's Democratic Republic (PDR) is still considered a highly endemic country for hepatitis B, mainly due to perinatal transmission of hepatitis B virus (HBV), despite efforts made since 2004 for universal immunization of newborns. The prevalence of HBV surface antigen (HBsAg) carriage in pregnant women is a relevant marker for the risk of mother-to-child HBV transmission. This study aimed to assess the changes in prevalence of HBV infection among pregnant women attending the Mahosot Prenatal Clinic (Vientiane Capital). Methods. A retrospective study was performed in the Mahosot Hospital Laboratory to collect and analyze all the results of HBsAg testing in pregnant women from 2008 to 2014. Results. Of a total of 13,238 tested women of mean age of 26 years, 720 women (5,44% [95 CI: 5.1-5.8%]) were found HBsAg positive, the annual prevalence ranging from 4.6% to 6.2%. A slight but steady and significant decrease in prevalence over the 7 years of the study could be documented. Conclusion. Although below the 8% hyperendemic threshold, the HBsAg prevalence observed in pregnant women in Vientiane reflects a high risk of HBV perinatal transmission and call for a widespread infant immunization with an HBV vaccine birth dose.

High prevalence of intestinal worms in children up to 5 years of age in Huaphan province, Lao People's Democratic Republic (PDR).

BACKGROUND: The prevalence of soil-transmitted helminth infection is high in Lao People's Democratic Republic (PDR), reaching 62% among school-children. However, this prevalence presents wide regional variations, due to differences in healthcare access and environmental factors. Curiously, there are few studies on helminth infections in pre-school children - an age group targeted by the national de-worming campaign. Therefore, a preliminary study was conducted in a remote region of Huaphan Province, North Laos, to determine the prevalence of helminth infections in pre-school children. RESULTS: A total of 74 pre-school aged children provided stool samples for this study. Parasite eggs were detected in 41.9% with Ascaris lumbricoides being most common (32.4%). Presence of parasites was significantly associated with distance from health centres. CONCLUSIONS: Such a high prevalence of helminth infection indicates that the national deworming campaign is not adequate in the remote areas, in particular in villages distant from health care centres. It is necessary to ensure the proper administration of anti-helminthics to all children and to adapt the implementation of deworming campaigns to the specificities of each province.

Hydrological Regime and Water Shortage as Drivers of the Seasonal Incidence of Diarrheal Diseases in a Tropical Montane Environment.

BACKGROUND: The global burden of diarrhea is a leading cause of morbidity and mortality worldwide. In montane areas of South-East Asia such as northern Laos, recent changes in land use have induced increased runoff, soil erosion and in-stream suspended sediment loads, and potential pathogen dissemination. To our knowledge, few studies have related diarrhea incidences to catchment scale hydrological factors such as river discharge, and loads of suspended sediment and of Fecal Indicator Bacteria (FIB) such as Escherichia coli, together with sociological factors such as hygiene practices. We hypothesized that climate factors combined with human behavior control diarrhea incidence, either because higher rainfall, leading to higher stream discharges, suspended sediment loads and FIB counts, are associated with higher numbers of reported diarrhea cases during the rainy season, or because water shortage leads to the use of less safe water sources during the dry season. Using E. coli as a FIB, the objectives of this study were thus (1) to characterize the epidemiological dynamics of diarrhea in Northern Laos, and (2) to identify which hydro-meteorological and sociological risk factors were associated with diarrhea epidemics. METHODS: Considering two unconnected river catchments of 22 and 7,448 km2, respectively, we conducted a retrospective time series analysis of meteorological variables (rainfall, air temperature), hydrological variables (discharge, suspended sediments, FIB counts, water temperature), and the number of diarrheal disease cases reported at 6 health centers located in the 5 southern districts of the Luang Prabang Province, Lao PDR. We also examined the socio-demographic factors potentially affecting vulnerability to the effect of the climate factors, such as drinking water sources, hygiene habits, and recreational water exposure. RESULTS: Using thus a mixed methods approach, we found E. coli to be present all year long (100-1,000 Most Probable Number or MPN 100 mL-1) indicating that fecal contamination is ubiquitous and constant. We found that populations switch their water supply from wells to surface water during drought periods, the latter of which appear to be at higher risk of bacterial contamination than municipal water fountains. We thus found that water shortage in the Luang Prabang area triggers diarrhea peaks during the dry and hot season and that rainfall and aquifer refill ends the epidemic during the wet season. The temporal trends of reported daily diarrhea cases were generally bimodal with hospital admissions peaking in February-March and later in May-July. Annual incidence rates were higher in more densely populated areas and mostly concerned the 0-4 age group and male patients. CONCLUSIONS: We found that anthropogenic drivers, such as hygiene practices, were at least as important as environmental drivers in determining the seasonal pattern of a diarrhea epidemic. For diarrheal disease risk monitoring, discharge or groundwater level can be considered as relevant proxies. These variables should be monitored in the framework of an early warning system provided that a tradeoff is found between the size of the monitored catchment and the frequency of the measurement.

Antibiotic prescription behaviours in Lao People's Democratic Republic: a knowledge, attitude and practice survey.

OBJECTIVE: To assess the antibiotic prescribing practices of doctors working in the Lao People's Democratic Republic and their knowledge of local antibiotic resistance patterns. METHODS: Doctors attending morning meetings in 25 public hospitals in four provinces were asked to complete a knowledge, attitude and practice survey. The questionnaire contained 43 multiple choice questions that the doctor answered at the time of the meeting. FINDINGS: The response rate was 83.4% (386/463). Two hundred and seventy doctors (59.8%) declared that they had insufficient information about antibiotics. Only 14.0% (54/386) recognized the possibility of cephalosporin cross-resistance in methicillin-resistant Staphylococcus aureus. Most participants had no information about local antibiotic resistance for Salmonella Typhi (211/385, 54.8%) and hospital-acquired pneumonia (253/384, 65.9%). Unnecessary antibiotic prescriptions were considered as harmless by 115 participants and 148 considered locally-available generic antibiotics to be of poor quality. Nearly three-quarters (280/386) of participants agreed that it was difficult to select the correct antibiotics. Most participants (373/386) welcomed educational programmes on antibiotic prescribing and 65.0% (249/383) preferred local over international antibiotic guidelines. CONCLUSION: Doctors in the Lao People's Democratic Republic seem to favour antibiotic prescribing interventions. Health authorities should consider a capacity building programme that incorporates antibiotic prescribing and hospital infection control.

Diphtheria in Lao PDR: Insufficient Coverage or Ineffective Vaccine?

BACKGROUND: During late 2012 and early 2013 several outbreaks of diphtheria were notified in the North of the Lao People's Democratic Republic. The aim of this study was to determine whether the re-emergence of this vaccine-preventable disease was due to insufficient vaccination coverage or reduction of vaccine effectiveness within the affected regions. METHODS: A serosurvey was conducted in the Huaphan Province on a cluster sampling of 132 children aged 12-59 months. Serum samples, socio-demographic data, nutritional status and vaccination history were collected when available. Anti-diphtheria and anti-tetanus IgG antibody levels were measured by ELISA. RESULTS: Overall, 63.6% of participants had detectable diphtheria antibodies and 71.2% tetanus antibodies. Factors independently associated with non-vaccination against diphtheria were the distance from the health centre (OR: 6.35 [95% CI: 1.4-28.8], p = 0.01), the Lao Theung ethnicity (OR: 12.2 [95% CI:1,74-85, 4], p = 0.01) and the lack of advice on vaccination given at birth (OR: 9.8 [95% CI: 1.5-63.8], (p = 0.01) while the level of maternal edu-cation was a protective factor (OR: 0.08 [95% CI: 0.008-0.81], p = 0.03). Most respondents claimed financial difficulties as the main reason for non-vaccination. Out of 55 children whose vaccination certificates stated that they were given all 3 doses of diphtheria-containing vaccine, 83.6% had diphtheria antibodies and 92.7% had tetanus antibodies. Furthermore, despite a high prevalence of stunted and underweight children (53% and 25.8%, respectively), the low levels of anti-diphtheria antibodies were not correlated to the nutritional status. CONCLUSIONS: Our data highlight a significant deficit in both the vaccination coverage and diphtheria vaccine effectiveness within the Huaphan Province. Technical deficiencies in the methods of storage and distribution of vaccines as well as unreliability of vaccination cards are discussed. Several hypotheses are advanced to explain such a decline in immunity against diphtheria and recommendations are provided to prevent future outbreaks.

Hepatitis B virus in the Lao People's Democratic Republic: a cross sectional serosurvey in different cohorts.

BACKGROUND: Despite hepatitis B vaccination at birth and at 6, 10 and 14 weeks of age, hepatitis B virus (HBV) infection continues to be endemic in the Lao People's Democratic Republic (PDR). We carried out a cross-sectional serological study in infants, pre-school children, school pupils and pregnant women to determine their burden of disease, risk of infection and vaccination status. METHODS: A total of 2471 participants between 9 months and 46 years old were recruited from urban (Vientiane Capital, Luang Prabang), semi-urban (Boulhikhamxai and Savannakhet) and remote rural areas (Huaphan). All sera were tested for anti-HBs and anti-HBc. Sera testing positive for anti-HBc alone were further tested for the presence of HBsAg. RESULTS: A low prevalence of HBsAg (0.5%) was detected among infants from Vientiane and Luang Prabang, indicating some success of the vaccination policy. However, only 65.6% had protective anti-HBs antibodies, suggesting that vaccination coverage or responses remain sub-optimal, even in these urban populations.In pre-school children from remote areas in Huaphan, 21.2% were positive for anti-HBc antibodies, and 4.6% were for HBsAg positive, showing that a significant proportion of children in these rural regions have early exposure to HBV. In pre-school children with 3 documented HBV vaccinations, only 17.0% (15/55) were serologically protected.Among school-children from semi-urban regions of Luang Prabang, Boulhikhamxai and Savannakhet provinces, those below the age of 9 who were born after HBV vaccine introduction had anti-HBc and HBsAg prevalence of 11.7% and 4.1%, respectively. The prevalence increased to 19.4% and 7.8% of 10-14 year olds and to 27% and 10.2% of 15-19 year olds.Pregnant women from Luang Prabang and Vientiane had very high anti-HBc and HBsAg prevalence (49.5% and 8.2%), indicating high exposure and risk of onward vertical transmission to the unborn infant. CONCLUSIONS: Overall, the results demonstrate a dramatic deficiency in vaccination coverage and vaccine responses and/or documentation within the regions of Lao PDR studied, which included urbanized areas with better health care access. Timely and effective hepatitis B vaccination coverage is needed in Lao PDR.

Vaccination status, knowledge and awareness towards hepatitis B among students of health professions in Vientiane, Lao PDR.

Health care workers (HCW) are a population at high risk of hepatitis B virus (HBV) infection, especially in endemic countries such as Lao PDR. Effective vaccines are available since over 10 years, but many HCWs are not aware of the risk of infection and are still not immunized against hepatitis B. This study aimed to assess immunization coverage against hepatitis B among the students of the University of Health Sciences (UHS) of Lao PDR in 2013 and to look for the causes of non-vaccination. A cross-sectional survey was conducted by self-administered questionnaire on a representative stratified sample of each academic year in each faculty. In total, 961 questionnaires were collected, Basic Sciences: 143, Medicine: 167, Pharmacy: 148, Dentistry: 139, Nursing Sciences: 159, Medical Technology: 99, and Postgraduate Studies: 106. Respondents were predominantly female (59.1%), mean age 25.1±7.0 years, single (76.3%), from the provinces (68.0%), of the Lao Loum ethnic group (84.4%). Among them, 21% were fully vaccinated against hepatitis B and 9.5% partially. Immunization coverage rates were significantly higher among women (p=0.01), students aged over 25 years, married or belonging to the post-graduate faculty (p<0.001). The most common reason (38.6%) given for non-vaccination was not knowing where to get vaccinated. Knowledge about hepatitis B, scored from 0 to 5, was poor (0-1) for 86.5% of the students, but 77.5% were aware of the hepatitis B vaccine. The knowledge scores were significantly higher for students aged over 25 years, married or post-graduated (p<0.001). Vaccination coverage against hepatitis B is dramatically low among students of health professions in Laos, largely because of their lack of knowledge and awareness. Upon admission to the University, all future HCWs should receive information about the occupational risks of blood-borne viruses transmission and be encouraged to get vaccinated against hepatitis B.

Knowledge, awareness and attitudes about cervical cancer among women attending or not an HIV treatment center in Lao PDR.

BACKGROUND: Cervical cancer is the first female cancer in Lao PDR, a low-income country with no national screening and prevention programs for this human papillomavirus (HPV) associated pathology. HIV-infected women have a higher risk of persistent oncogenic HPV infection.The purpose of this study was to determine the knowledge, awareness and attitudes about cervical cancer among Lao women attending or not an HIV treatment center, in order to understand if this attendance had offered an opportunity for information and prevention. METHODS: A cross-sectional case-control survey was conducted in three provinces of Lao PDR, Vientiane, Luang Prabang and Savannakhet. Cases were 320 women aged 25 to 65, living with HIV and followed in an HIV treatment center. Controls were 320 women matched for age and place of residence, not attending an HIV treatment center. RESULTS: Cases had a greater number of sexual partners and used condoms more often than controls. Only 36.6% of women had consulted a gynecologist (47.5% among cases and 25.6% among controls, p < 0.001) and 3.9% had benefited from at least one Pap smear screening (5.6% cases and 2.2% controls, p = 0.02). The average knowledge score was 3.5 on a 0 to 13 scale, significantly higher in cases than in controls (p < 0.0001). Despite having a lower education level and economic status, the women living with HIV had a better knowledge about cervical cancer and were more aware than the controls of the risk of developing such a cancer (35.9% vs. 8.4%, p = 0.0001). The main source of information was healthcare professionals. The main reasons for not undergoing Pap smear were the absence of symptoms and the default of medical injunction for cases, the lack of information and ignorance of screening usefulness for controls. CONCLUSION: In Lao PDR, routine consultation in HIV treatment centers is not enough harnessed to inform women of their high risk of developing cervical cancer, and to perform screening testing and treatment of precancerous lesions. Implementing this cost-effective strategy could be the first step toward a national prevention program for cervical cancer.

Investigating epilepsy in Africa: 10 years of data collection using a standardized questionnaire in 2,269 peoples with epilepsy.

PURPOSE: The need for comparable epidemiologic data on epilepsy from various locations in tropical areas has led in 1994 to the creation of a questionnaire able to standardize information. The Limoges' questionnaire was created to collect information independently of the objectives of each survey performed, and since it has been employed in various continents under tropics latitude. In Africa between 1994 and 2004, 13 epidemiologic surveys in 12 countries were performed by this means. Authors of these works were solicited to communicate their raw data on people with epilepsy (PWE). METHODS: Information collected was aggregated in a database upon which operations of data management were processed. Undernutrition status was determined using an anthropologic method, according World Health Organization (WHO) recommendations. Factors associated with undernutrition and absence of treatment by phenobarbitone were searched for by using multivariate logistic regression. KEY FINDINGS: Information about 2,269 PWE was collected. Mean treatment gap and undernutrition were determined, respectively, to be 30.6% [95% confidence interval (95% CI) 28.7-32.6] and 25.4% (95% CI 22.7-28.2). Factors significantly associated with undernutrition and not being treated with phenobarbitone were determined. SIGNIFICANCE: Despite the different purposes of each study, we were able to pool information in order to characterize and study particular traits of PWE in Africa. Some items of particular importance should be collected systematically and will be highlighted in a newer version of this questionnaire. Because many surveys were undertaken using this tool in tropical areas, a backward compatibility should be ensured.

Understanding the differences in prevalence of epilepsy in tropical regions.

Epilepsy is a frequent chronic neurologic disorder that affects nearly 70 million people worldwide. The majority of people with epilepsy live in developing countries, where epilepsy remains a major public health problem. Wide prevalence differences exist among various populations across sub-Saharan Africa, Latin America, and Asia. In particular, prevalence is lower in Southeast Asia than in sub-Saharan Africa and Latin America. Methodologic problems alone do not seem to explain these differences shown in recent review papers. The distribution of numerous risk or etiologic factors such as infectious diseases with neurologic sequel, head injuries, or genetic factors could explain these differences. Stigmatization of people with epilepsy could lead to underestimating the prevalence of epilepsy, even in well-conducted studies. It is important to standardize the process of epidemiologic monitoring of epilepsy in order to improve the reliability in data comparison. Understanding the reasons for these differences is a crucial issue for eventually raising new hypotheses or prevention strategies.

Determining the burden of neurological disorders in populations living in tropical areas: who would be questioned? Lessons from a Mexican rural community.

BACKGROUND: The best approach to determine the burden of neurological disorders in developing countries is to perform population-based studies. Our objectives were to determine the prevalence of neurological disorders in a Mexican rural community and assess the usefulness of a household screening questionnaire. METHODS: The survey took place in a Mexican rural community of Puebla State in Mexico. This was a cross-sectional, population-based, 2-phase study including a comparison of the usefulness levels of the individual (IQ) and household (HQ) questionnaires. RESULTS: A total of 4,008 individuals participated in the prevalence study using the IQ; of these, 280 neurological examinations allowed to identify 127 individuals suffering from at least 1 neurological disease. The most frequent ailments were headache (22.4/1,000, 95% confidence interval, CI: 17.7-28.2), neuropathy (7.1/1,000, CI 95%: 4.4-11.3) and epilepsy (3.9/1,000, CI 95%: 2.3-6.5). The HQ, used in parallel with the IQ, detected significantly fewer neurological cases. This result was mainly due to the low capacity of the HQ to detect headache. CONCLUSIONS: Results of the prevalence study are discussed emphasizing their relevance in adequately allocating resources. The usefulness of the HQ for screening neurological disorders in general was low, but could be adequate for specific neurological disorders.

Meta-analysis of the association between cysticercosis and epilepsy in Africa.

PURPOSE: The association between cysticercosis and epilepsy has been widely studied in Latin America and Asia and has proven to be one of the main causes of epilepsy. Despite high prevalences of both diseases in Africa, their association remains unclear. In this article we quantified the strength of the association between epilepsy and cysticercosis in Africa and we proposed some guidelines for future studies. METHODS: We performed a systematic review of literature on cysticercosis (considered as exposure) and epilepsy (considered as the disease) and collected data from both cross-sectional and case-control studies. A common odds ratio was estimated using a random-effects meta-analysis model of aggregate published data. RESULTS: Among 21 retrieved documents, 11 studies located in 8 African countries were included in the meta-analysis. Odds ratio of developing epilepsy when presenting cysticercosis (defined as Taenia solium seropositivity) ranged from 1.3-6.1. Overall, association between cysticercosis and epilepsy was found significant with a common odds ratio of 3.4 [95% confidence interval (CI) 2.7-4.3; p < 0.001]. DISCUSSION: The variability of the association found between the studies could be due to differences in study design or in pathogenesis of cysticercosis. Further studies should overcome identified problems by following some guidelines to improve epidemiologic and clinical assessment of the association. Better understanding of the relation between cysticercosis and epilepsy is a key issue in improving prevention of epilepsy in Africa.

The disease burden of Taenia solium cysticercosis in Cameroon.

BACKGROUND: Taenia solium cysticercosis is an important zoonosis in many developing countries. Human neurocysticercosis is recognised as an important cause of epilepsy in regions where the parasite occurs. However, it is largely underreported and there is a lack of data about the disease burden. Because a body of information on human and porcine cysticercosis in Cameroon is becoming available, the present study was undertaken to calculate the impact of this neglected zoonosis. METHODS: Both the cost and Disability Adjusted Life Year (DALY) estimations were applied. All necessary parameters were collected and imported in R software. Different distributions were used according to the type of information available for each of the parameters. FINDINGS: Based on a prevalence of epilepsy of 3.6%, the number of people with neurocysticercosis-associated epilepsy was estimated at 50,326 (95% CR 37,299-65,924), representing 1.0% of the local population, whereas the number of pigs diagnosed with cysticercosis was estimated at 15,961 (95% CR 12,320-20,044), which corresponds to 5.6% of the local pig population. The total annual costs due to T. solium cysticercosis in West Cameroon were estimated at 10,255,202 Euro (95% CR 6,889,048-14,754,044), of which 4.7% were due to losses in pig husbandry and 95.3% to direct and indirect losses caused by human cysticercosis. The monetary burden per case of cysticercosis amounts to 194 Euro (95% CR 147-253). The average number of DALYs lost was 9.0 per thousand persons per year (95% CR 2.8-20.4). INTERPRETATION: This study provides an estimation of the costs due to T. solium cysticercosis using country-specific parameters and including the human as well as the animal burden of the zoonotic disease. A comparison with a study in South Africa indicates that the cost of inactivity, influenced by salaries, plays a predominant role in the monetary burden of T. solium cysticercosis. Therefore, knowing the salary levels and the prevalence of the disease might allow a rapid indication of the total cost of T. solium cysticercosis in a country. Ascertaining this finding with additional studies in cysticercosis-endemic countries could eventually allow the estimation of the global disease burden of cysticercosis. The estimated number of DALYs lost due to the disease was higher than estimates already available for some other neglected tropical diseases. The total estimated cost and number of DALYs lost probably underestimate the real values because the estimations have been based on epilepsy as the only symptom of cysticercosis.

Inexpensive anti-cysticercosis vaccine: S3Pvac expressed in heat inactivated M13 filamentous phage proves effective against naturally acquired Taenia solium porcine cysticercosis.

In search of reducing vaccine production costs', a recombinant M13 phage version of the anti-cysticercosis tripeptide vaccine (S3Pvac) was developed. The efficacy of S3Pvac-Phage vs. placebo was evaluated in a randomized trial that included 1,047 rural pigs in 16 villages of Central Mexico. Three to five months after vaccination 530 pigs were examined by tongue inspection. At 5-27 months of age, 331 pigs (197 vaccinated/134 controls) were inspected at necropsy. Vaccination reduced 70% the frequency of tongue cysticercosis and, based on necropsy, 54% of muscle-cysticercosis and by 87% the number of cysticerci.