Evaluating TB diagnosis and care in the Union of the Comoros.

SETTING: The Union of the Comoros has experienced a persistent notification gap in TB cases despite several strategic changes, including molecular diagnosis and contact investigation. We therefore performed a TB patient pathway analysis (PPA) under the National Tuberculosis Programme (NTP). OBJECTIVE: To assess the alignment of healthcare-seeking behaviour and TB service availability to clarify the reasons for these missing cases. DESIGN: Three primary data sources, including a national list of health facilities, TB surveillance data and care-seeking behaviour data, were analysed at the national and regional levels to determine access to TB diagnosis and the initial point of care-seeking. Summary data were visualised using the standardised PPA Wizard programme, and the analysis was completed using demographic and socio-economic data. RESULTS: At the initial point of care-seeking, 18% of patients had access to TB services, available only in nine centralised public health facilities. Furthermore, 30% of patients initially consulted in the informal sector and 45% in the formal public or private sector in health facilities, both of which lacked the capacity for TB diagnosis or first-line treatment. CONCLUSION: The concentration of and limited access to TB services at the intermediate and central levels of care indicate a need for decentralisation efforts.

CONTEXTE: L'Union des Comores a enregistré un déficit persistant de notifications de cas de TB malgré plusieurs changements stratégiques, comme la mise en place du diagnostic moléculaire et de la recherche des contacts. Nous avons donc réalisé une analyse du parcours des patients atteints de TB dans le cadre du Programme national de lutte contre la TB (NTP). OBJECTIF: Évaluer la concordance entre le comportement en matière de recherche de soins et la disponibilité des services de lutte contre la TB afin de clarifier les raisons de ces cas manquants. MÉTHODES: Trois sources de données primaires, dont une liste nationale des établissements de santé, des données de surveillance de la TB et des données sur les comportements en matière de recherche de soins, ont été analysées aux niveaux national et régional pour déterminer l'accès au diagnostic de la TB et le point initial de la recherche de soins. Les données récapitulatives ont été visualisées à l'aide du programme Wizard d'analyse standardisée du parcours du patient, et l'analyse a été complétée à l'aide de données démographiques et socio-économiques. RÉSULTATS: Au point de départ de la recherche de soins, 18% des patients avaient accès aux services de lutte contre la TB, disponibles uniquement dans neuf établissements de santé publics centralisés. Par ailleurs, 30% des patients ont initialement consulté dans le secteur informel et 45% dans le secteur formel (établissements de santé publics ou privés), qui manquent tous deux des capacités nécessaires au diagnostic de la TB ou au traitement de première ligne. CONCLUSION: La concentration et l'accès limité aux services de lutte contre la TB aux niveaux intermédiaire et central de soins sont révélateurs des efforts à entreprendre en matière de décentralisation.

Gatifloxacin is superior to levofloxacin and moxifloxacin in shorter treatment regimens for multidrug-resistant TB.

SETTING: Data were collected from patients starting one of the shorter treatment regimens (STRs) for multidrug-resistant tuberculosis (MDR-TB) in Bangladesh, Niger or Cameroon.OBJECTIVE: To estimate the effect of either a gatifloxacin (GFX), moxifloxacin (MFX) or levofloxacin (LVX) based STR on bacteriological effectiveness.DESIGN: Retrospective study of prospectively collected data.RESULTS: Among 1530 patients, bacteriological effectiveness was 96.7% overall. Stratified by treatment with a GFX-, LVX- or MFX-based regimen effectiveness was respectively 97.5%, 95.5% and 94.7%. Compared to those on a GFX-based regimen, the estimated summary odds ratio of having an adverse outcome was more than double (OR 2.05, 95% CI 1.09-3.90) in patients treated with either an LVX-based or MFX-based regimen. After adjusting for initial resistance, patients treated with an LVX-based regimen and MFX-based regimen had respectively a 4.5- and 8.4-fold times larger odds of an adverse bacteriological outcome. None among 859 patients at risk treated with a GFX-based compared to at least 4 of 228 among those on an MFX-based regimen acquired fluoroquinolone resistance.CONCLUSION: GFX-based regimens had superior bacteriological effectiveness than MFX-based or LVX-based regimens. As GFX is currently unavailable in most MDR-TB programs, its reintroduction should be prioritised.

Rifampicin resistance in new bacteriologically confirmed pulmonary tuberculosis patients in Cameroon: a cross-sectional survey.

OBJECTIVE: In Cameroon, tuberculosis (TB) cases are diagnosed and treated within a nationwide network of 248 diagnostic and treatment centres. In 2016, the centers notified a total of 175 multidrug-resistant (MDR-)TB cases, most of them retreatment cases. According to the WHO, the expected number of MDR-TB cases was estimated to be 1200 (1000-2200) corresponding to a rate of 6.8 (4.3-9.4) per 100,000 population. This indicates a notification gap of more than 80%. The objective of this study was to estimate the prevalence of MDR-TB in new bacteriologically confirmed pulmonary TB cases. We undertook a nationwide cross sectional survey during 6 weeks. RESULTS: During the study period, the NTP notified 1478 new bacteriologically confirmed pulmonary TB cases. Among them, 1029 (70%) had a valid Xpert result and 16 were identified with rifampicin resistant (RR-TB), a tracer of MDR-TB. This gives a prevalence of 1.6% (95% CI 0.8-2.3) among incident cases. The rate of RR-TB in the regions varied between 0 and 3.3%. If the results of this study are confirmed, the incidence rate given by WHO (2.8%, 95% CI 2.1-3.4) might be an over-estimation.

Treatment outcome with a short multidrug-resistant tuberculosis regimen in nine African countries.

SETTING: Nine countries in West and Central Africa. OBJECTIVE: To assess outcomes and adverse drug events of a standardised 9-month treatment regimen for multidrug-resistant tuberculosis (MDR-TB) among patients never previously treated with second-line drugs. DESIGN: Prospective observational study of MDR-TB patients treated with a standardised 9-month regimen including moxifloxacin, clofazimine, ethambutol (EMB) and pyrazinamide (PZA) throughout, supplemented by kanamycin, prothionamide and high-dose isoniazid during an intensive phase of a minimum of 4 to a maximum of 6 months. RESULTS: Among the 1006 MDR-TB patients included in the study, 200 (19.9%) were infected with the human immunodeficiency virus (HIV). Outcomes were as follows: 728 (72.4%) cured, 93 (9.2%) treatment completed (81.6% success), 59 (5.9%) failures, 78 (7.8%) deaths, 48 (4.8%) lost to follow-up. The proportion of deaths was much higher among HIV-infected patients (19.0% vs. 5.0%). Treatment success did not differ by HIV status among survivors. Fluoroquinolone resistance was the main cause of failure, while resistance to PZA, ethionamide or EMB did not influence bacteriological outcome. The most important adverse drug event was hearing impairment (11.4% severe deterioration after 4 months). CONCLUSIONS: The study results support the use of the short regimen recently recommended by the World Health Organization. Its high level of success even among HIV-positive patients promises substantial improvements in TB control.

Epidemiology of tuberculosis in Cameroon as mirrored in notification data, 2006-2014.

SETTING: The Cameroonian National Tuberculosis Programme. OBJECTIVES: To assess case surveillance data for the 9-year period between January 2006 and December 2014. DESIGN: Retrospective descriptive analysis of tuberculosis (TB) case finding in Cameroon using routine surveillance data. Data on sociodemographic characteristics, disease category, clinical and laboratory variables, and geographic regions were analysed. RESULTS: The absolute number of TB cases (all forms) notified increased from 24 878 in 2006 to 26 517 in 2014; however, the population-adjusted annual case notification rate (CNR) of TB (all forms) as well as that of new smear-positive pulmonary TB cases decreased significantly, from 139 to 121 (P < 0.001) and from 77 to 70/100 000 population (P < 0.02), respectively. The human immunodeficiency virus (HIV) infection rate reported among all TB cases (39% in 2014) remained stable from 2009. The male-to-female ratio also remained stable, with a slight shift towards older age. There was a CNR gradient from the north to the south that appears to be related to HIV infection rates, population density and access to health services. CONCLUSIONS: TB CNRs in Cameroon for the 2006-2014 period show a slow but steady decrease, and there are indications that the trend reflects incidence. However, there is evidence to suggest that TB transmission is still ongoing.

Sputum bacterial load predicts multidrug-resistant tuberculosis in retreatment patients: a case-control study.

BACKGROUND: Rapid and effective diagnosis of multidrug-resistant tuberculosis (MDR-TB) is an essential component of global tuberculosis (TB) control, but most MDR-TB cases are still not diagnosed. OBJECTIVE: To assess whether patient sputum bacterial load can be used to identify patients at increased risk of MDR-TB. METHODS: We used a case-control study and multivariable logistic regression models to investigate associations between MDR-TB and sputum bacterial load, as measured by semi-quantitative microscopy and automated time to detection (TTD) of liquid culture. We assessed data from retreatment TB patients with MDR-TB (cases) and from those without MDR-TB (controls) at a reference laboratory in Cameroon. RESULTS: MDR-TB was associated with a smear microscopy grade of 3+ (OR 21.9, 95%CI 6.2-76.8) or 2+ (OR 10.8, 95%CI 2.9-40.7), compared to a result of 1+, scanty or smear-negative among 80 MDR-TB cases and 521 controls. MDR-TB was associated with automated TTD of â©¿160 h (OR 2.2, 95%CI 1.1-4.7) compared to >160 h among a subpopulation of 47 cases and 350 controls. CONCLUSIONS: A higher sputum bacterial load is associated with MDR-TB in retreatment patients in Cameroon.

Mycobacterium tuberculosis resistance in pulmonary TB patients in Cameroon: a phenotypic susceptibility assay.

OBJECTIVE: To determine the resistance of Mycobacterium tuberculosis to first- and second-line agents in adult pulmonary tuberculosis (TB) patients in Cameroon using a novel phenotypic assay. SETTING: Samples were collected from TB patients at Bamenda Hospital in Bamenda, Cameroon. DESIGN: Samples were collected consecutively from adult pulmonary TB patients over a 2-month period. TREK Sensititre(TM) MYCOTB panels were used to perform phenotypic drug susceptibility testing (DST). Susceptibility/resistance was determined by comparing minimum inhibitory concentrations to standard critical concentrations established for first- and second-line anti-tuberculosis drugs. RESULTS: Of 103 sputum samples processed, growth on Löwenstein-Jensen media was confirmed in 78 samples, 65 of which were suitable for DST. Thirty-nine strains (60%) were susceptible to all first- and second-line drugs. Five strains (8%) were categorized as multidrug-resistant TB. Two strains (3%) were classified as pre-extensively drug-resistant TB. Of those isolates susceptible to first-line drugs, 20% were resistant to at least one second-line drug. CONCLUSION: Antimicrobial resistance may be higher than assumed in TB strains in Cameroon, especially with regard to second-line drugs. There remains a need for rapid, comprehensive DST.

High effectiveness of a 12-month regimen for MDR-TB patients in Cameroon.

SETTING: Two specialised multidrug-resistant tuberculosis (MDR-TB) treatment units in Cameroon. OBJECTIVE: To assess outcome and adverse drug events with a standardised 12-month regimen for MDR-TB among second-line drug naïve patients. DESIGN: Prospective observational study of MDR-TB patients treated with a standardised 12-month regimen including gatifloxacin, clofazimine, prothionamide, ethambutol and pyrazinamide throughout, supplemented by kanamycin and isoniazid during an intensive phase of a minimum of 4 months. Progress was monitored monthly until treatment completion and twice over one year after treatment cessation. RESULTS: Eighty-seven potentially eligible patients were lost and never treated due to delayed availability of test results. Among the 150/236 eligible and treated patients, 134 (89%) successfully completed treatment, 10 died, 5 were lost, 1 failed and none relapsed. The patients' mean age was 33.7 years (range 17-68), 73 (49%) were females, 120 (80%) had failed on previous treatment, 30 (20%) were human immunodeficiency virus seropositive, 62 (43%) had a body mass index <18.5 kg/m(2) and 41 (27%) had radiographic involvement of five or six of the six lung zones. The most important adverse drug event was hearing impairment, which occurred in 46 of 106 (43%) patients. CONCLUSIONS: These results add further evidence for the usefulness of shorter, standardised regimens among patients without second-line drug resistance.

Tuberculosis incidence in Cameroonian prisons: a 1-year prospective study.

BACKGROUND: Rates of tuberculosis (TB) transmission in prisons are reported to be high worldwide. However, a recent systematic review identified only 19 published studies reporting TB incidence in prisons, most of them from the last century and only one from sub-Saharan Africa. OBJECTIVES: To assess the persisting risk of smear-positive pulmonary tuberculosis (PTB) among prison populations benefiting from a comprehensive TB/HIV control programme in Cameroon, compared with that in the community. METHODS: This descriptive and prospective study evaluated PTB incidence rates over a 1-year period. The study population was inmates of 10 major prisons, sampled by convenience, comprising about 45% of the country's prison population. As PTB incident cases, all prisoners with incident PTB after a prison stay of > or = 90 days were considered. The prison TB incidence rate was compared with that of the corresponding male population in the community. RESULTS: The mean annual PTB incidence in Cameroonian prisons in this study was 1 700 cases in 100 000 person-years at risk, the incidence rate ratio being 9.4 (95% confidence interval 8.1-10.9). CONCLUSION: Findings suggest that internationally recommended prison TB control measures alone may not help protect prisoners from within-prison spread of TB. Imprisonment policies and conditions therefore require fundamental changes.

Spatial analysis of tuberculosis in Douala, Cameroon: clustering and links with socio-economic status.

SETTING: Douala, the economic capital of Cameroon, with a network of 20 diagnostic and treatment centres for tuberculosis (TB). OBJECTIVE: To describe the spatial distribution of smear-positive pulmonary tuberculosis (PTB) cases in Douala, Cameroon, and to evaluate links between PTB incidence and patients' socio-economic status (SES). DESIGN: Between May 2011 and April 2012, demographic clinical characteristics and global positioning system coordinates for the residence of each consenting PTB case were collected. Spatial scan statistic was used to identify spatial clusters of tuberculosis. SES data were collected by interview during home visits. PTB patients' SES data were compared with those available for the whole urban population from a recent demographic and health survey. The correlation between PTB incidence and the mean SES of the PTB patients was examined by health area (HA). RESULTS: In total, 2132 (84%) diagnosed PTB cases were identified and interviewed. Three statistically significant spatial clusters were identified. High PTB incidence was predominantly found in HAs characterised by low SES. CONCLUSION: There is evidence of clustering of PTB cases in Douala. Clusters are mainly found in neighbourhoods of low SES. Systematic use of cluster detection techniques for regular TB surveillance in Cameroon might aid in the effective deployment of National TB Programme resources.

Mycobacterium tuberculosis complex strains and drug susceptibility in a cattle-rearing region of Cameroon.

SETTING: Seven district hospitals in the Adamaoua Region of Cameroon, June 2009 to May 2010. OBJECTIVES: To identify species among Mycobacterium tuberculosis complex (MTC) strains responsible for pulmonary tuberculosis (PTB) and determine their susceptibility to anti-tuberculosis drugs. DESIGN: Sputum specimens were collected from 509 consecutively admitted adults and cultured. Identification of cultured strains was mainly based on culture growth characteristics and standard biochemical tests with spoligotyping for confirmation on a subset of strains. Drug susceptibility testing was performed using the indirect proportion method. RESULTS: Growth of MTC strains occurred in specimens of 445/509 (87.4%) patients: 433 (97.3%) were identified as M. tuberculosis, 10 (2.3%) as M. africanum and 2 (0.4%) as M. bovis. The overall resistance rate was 7.9%, with 7.3% resistance in new cases and 21.1% in previously treated cases. Isoniazid resistance in new cases was most common (4.2%), followed by streptomycin (3.3%), rifampicin (1.9%) and ethambutol (0.9%). Multidrug-resistant tuberculosis was more frequent in previously treated than in new cases (10.5% vs. 1.4%, P < 0.05). CONCLUSION: Although the Adamaoua Region is a stock-farming area, M. tuberculosis is the predominant MTC species responsible for PTB. Anti-tuberculosis drug resistance in new and previously treated cases is well established, underscoring the need to reinforce the DOTS strategy.

Controlling tuberculosis in prisons against confinement conditions: a lost case? Experience from Cameroon.

BACKGROUND: Tuberculosis (TB) is recognised as a major public health problem in the prisons of sub-Saharan Africa. In Cameroon, the main prisons have created diagnostic and treatment units linked to the National Tuberculosis Programme (NTP). OBJECTIVE: To assess the effectiveness of routine TB control activities in a prison population by determining the prevalence of undetected pulmonary tuberculosis (PTB). METHODS: In 2009, a PTB case-finding survey was undertaken at the Central Prison of Yaounde (CPY), Cameroon. All prisoners with cough of ≥1 week's duration were screened by sputum smear microscopy. Smears were sent to the national reference laboratory for culture and drug susceptibility testing (DST). Voluntary testing for human immunodeficiency virus (HIV) was offered to all inmates. RESULTS: Among 3219 inmates screened, 40 (1.2%) identified with PTB had been missed by the prison TB control programme. Missed PTB was positively associated with severe crowding, low body mass index and previous TB treatment. Of the 40 inmates, four (10%) were TB-HIV co-infected. The DST of three inmates revealed resistance to anti-tuberculosis drugs. CONCLUSION: Despite a well-performing TB control programme in the CPY, the number of undetected PTB cases remains unacceptably high. It is doubtful whether TB transmission can be controlled under conditions of confinement, such as the CPY.

[Weather and cholera: epidemic in Douala, Cameroon in 2004]. / Météorologie et cholera: epidémie de Douala en 2004 (Cameroun).

A cholera epidemic was recorded in Douala, Cameroon in 1971. Another 8-month outbreak occurred in January 2004 and spread in rapid succession to all health districts in Douala. The purpose of this study was to assess the association between meteorology and cholera incidence and preventive action in the health districts.

Tuberculosis in Cameroon (2003-2008)

Background Cameroon re-established a National Tuberculosis Control Programme (NTCP) in 1997.The NTCP was restructured and recognized as a priority programme in 2002. Objective to present the organisation of the NTPC and the evaluation of its control activities from 2003 to 2008 after it's restructure. Design information and data were collected from TB policy documents of the Ministry of Health and from annual activity reports of the NTCP and analysed. Major achievements in TB control are highlighted and weaknesses and gaps identified .Results- The NTCP in a vertical programme with its activities organized at three levels .Forms 2003 to 2008; the number of detected smear positive pulmonary TB (ss+PTB) cases increased from 10;661 to 14;232 and that of TB from of 16;478 to 25;107 cases .The treatment success rate for new ss+PTB cases rose from 73in 76in 2007.The TB/HIV co-infection rate in 2008 was 40and 36for all forms of TB and for new ss+ PTB cases respectively. TB in prison is a major public health problem and multi -drug resistant TB (MDR-TR) is emerging .Several weaknesses and gaps in the programme have been identified. Conclusion: The activities of the NTCP from 2003 have been quite successful particularly in the area of the detection of new ss+PTB cases which has suppassed the 70target set by the programme.Treatment success rates even though improving fall below the 85NTCP target. The NTCP has several weaknesses and gaps which have to be tackled to make it more efficient. However the most important challenge remains a reliable source of funding to guarantee the programme's activities

Infection a VIH parmi les adultes atteints de tuberculose pulmonaire dans la region de L'ouest Cameroun

Afin de determiner la prevalence de l'infection a VIH parmi les adultes atteints de tuberculose pulmonaire bacteriologiquement confirmee par la culture dans la region Ouest du Cameroun et de preciser le role eventuel de certains antecedents et facteurs sociaux sur cette prevalence; nous avons inclus au cours d'une etude transversale menee entre avril 2004 et mars 2005 dans 18 centres de diagnostic et de traitement de la tuberculose; 604 malades ages de 15 ans et plus .Chaque malade inclus a ete interroge pour obtenir les informations socio-demographique et les donnees sur les antecedents de sejour en prison et de transfusion sanguine recente. La serologie VIH a ete determinee au moyen de deux tests rapides et confirmee par Western blot .Sur les 604 malades;173(28;6) presentaient une serologie positive pour le VIH1 ; il n'a pas ete retrouve une serologie positive pour le VIH2.Le taux de seropositivite au VIH etait de 24; 8pour les hommes et de 34;8pour les femmes (p=0;001).L'age moyen de femmes Co-infectees etait de 30.8 ans contre 34.8 ans pour les hommes seropositifs (p=0;005).La seroprevalence de l'infection a VIH etait statistiquement plus importante chez les femmes de tranche d'ages 34 ans que chez les hommes de la meme tranche d'age. Le taux de seropositivite pour le VIH etait egalement significativement superieur chez les patiences vivant en milieu urbain (p

Two vs. three sputum samples for microscopic detection of tuberculosis in a high HIV prevalence population.

SETTING: A busy urban hospital in Cameroon. OBJECTIVES: To compare the yield in bacteriologically proven tuberculosis (TB) cases examining two morning vs. three spot-morning-spot sputum specimens (MM vs. SMS) by direct microscopy for acid-fast bacilli (AFB). DESIGN: Repeated temporal cross-over between MM and SMS sampling for successive TB suspects, using culture as gold standard. RESULTS: A total of 799 suspects were screened using the MM strategy, identifying 223 smear-positives, and 808 suspects with the SMS strategy, yielding 236 smear-positives. Of the MM, 256 were culture-positive, of whom 195 (76%) were smear-positive. For SMS, these figures were respectively 281 and 206 (73%), a non-significant difference. The MM and SMS strategies also detected respectively 28 and 30 smear-positive cases not confirmed by culture. No cases were lost to treatment with either strategy. CONCLUSIONS: In this population with a high prevalence of human immunodeficiency virus (HIV) with late case presentation, smear microscopy of two morning specimens detected at least as many positive cases as the classical strategy, and no cases were lost before treatment. Two specimens for initial TB suspect screening can thus be recommended, also without excessive workload. Comparative studies in populations presenting with paucibacillary sputum are needed to determine the equivalent quality and yield of an alternative strategy with two spot specimens at consultation.

Diffuseur artisanal de chlore pour desinfecter les puits lors de l'epidemie de cholera de Douala (2004)

La chloration des puits est recommandee en cas d'epidemie de cholera. Mais les techniques de chloration sont mal codifiees; leur efficacite n'a pas ete prouvee; et l'on ne sait pas a quel rythme doit se faire la chloration. L'objectif etait de tester un dispositif artisanal de chloration continue; mesurer les taux de chlore residuel libre obtenus; et en suivre l'evolution; pour prevoir le delai de renouvellement. Dans 2 quartiers de Douala; 18 puits (9/quartier) ont fait l'objet de la mesure quotidienne pendant deux semaines du volume d'eau; du pH et du chlore residuel; apres installation d'un diffuseur artisanal a base de sable et d'hypochlorite de calcium dans un sachet plastique perfore; renouvele apres annulation des taux de chlore. La concentration maximumde chlore residuel libre a ete atteinte apres 1 jour (31 chlorations sur 36) ou 2 jours (5 sur 36). Elle est demeuree superieure au niveau minimum de 0;2mg/l pendant au moins 48 heures dans 33 des 36 chlorations. A J4; la moitie des puits avaient une concentration de chlore inferieure a 0;2 mg/l. La concentration de chlore etait plus elevee dans les puits familiaux que dans les puits communautaires .Malgre des difficultes de faisabilite et d'acceptabilite; le diffuseur propose a permis d'assurer la diffusion de chlore a des taux efficaces et non toxiques pendant 3 jours. Des systemes de diffusion plus prolongee et moins couteux devraient pouvoir etre proposes; dans le cadre d'actions integrees de lutte contre une epidemie de chlolera

[Handmade devices for continuous delivery of hypochlorite for well disinfection during the cholera outbreak in Douala, Cameroon (2004)]. / Diffuseur artisanal de chlore pour désinfecter les puits lors de l'épidémie de choléra de Douala (2004).

Well disinfection is generally recommended as an emergency response measure during cholera outbreaks. However few studies have been carried out to document chlorination techniques, prove the efficacy of chlorination, or determine how often disinfection should be performed. The purpose of this study was to test a handmade device for continuous chlorination, to measure the initial concentration of free residual chlorine, and monitor chlorine concentration to determine when renewal is necessary. Eighteen wells in 2 neighbors of Douala, Cameroon, i.e., 9 wells/neighborhood, were tested. Testing included daily measurement of water volume, pH, and residual chlorine for a period of two weeks after installing the handmade device composed of river sand and hypochlorite in a pre-perforated plastic bag that was renewed after disappearance of free residual chlorine. The maximum concentration of residual chlorine was reached after 1 day in 31 out of 36 chlorinations or 2 days in 5 out of 36. On day 4 the chlorine level was less than 0.2 mg/l in half of the wells. The chlorine concentration was higher in family than community wells. Notwithstanding feasibility and acceptability issues, the device allowed chlorination at effective nontoxic levels for 3 days. These findings open the possibility of developing devices allowing longer diffusion at lower cost for use within the framework of integrated cholera epidemic control programs.