Analytical framework to evaluate and optimize the use of imperfect diagnostics to inform outbreak response: Application to the 2017 plague epidemic in Madagascar.

During outbreaks, the lack of diagnostic "gold standard" can mask the true burden of infection in the population and hamper the allocation of resources required for control. Here, we present an analytical framework to evaluate and optimize the use of diagnostics when multiple yet imperfect diagnostic tests are available. We apply it to laboratory results of 2,136 samples, analyzed with 3 diagnostic tests (based on up to 7 diagnostic outcomes), collected during the 2017 pneumonic (PP) and bubonic plague (BP) outbreak in Madagascar, which was unprecedented both in the number of notified cases, clinical presentation, and spatial distribution.

Field assessment of dog as sentinel animal for plague in endemic foci of Madagascar.

The epidemiology of Yersinia pestis, the causative agent of plague, involves vectors and reservoirs in its transmission cycle. The passive plague surveillance in Madagascar targets mainly rodent and fleas. However, carnivores are routinely surveyed as sentinels of local plague activity in some countries.

Short- and long-term humoral immune response against Yersinia pestis in plague patients, Madagascar.

Background: Plague, a fatal disease caused by the bacillus, Yersinia pestis, still affects resources-limited countries. Information on antibody response to plague infection in human is scarce. Anti-F1 Ig G are among the known protective antibodies against Y.

Performance of plague rapid diagnostic test compared to bacteriology: a retrospective analysis of the data collected in Madagascar.

Background: Plague is a highly fatal disease caused by Yersinia pestis. Late diagnosis hampers disease outcome and effectiveness of control measures, induces death and disease spread. Advance on its diagnosis was the use of lateral flow rapid diagnostic test (RDT).

Trends of Human Plague, Madagascar, 1998-2016.

Madagascar is more seriously affected by plague, a zoonosis caused by Yersinia pestis, than any other country. The Plague National Control Program was established in 1993 and includes human surveillance. During 1998-2016, a total of 13,234 suspected cases were recorded, mainly from the central highlands; 27% were confirmed cases, and 17% were presumptive cases.

Burden and epidemiology of influenza- and respiratory syncytial virus-associated severe acute respiratory illness hospitalization in Madagascar, 2011-2016.

Background: Influenza and respiratory syncytial virus (RSV) infections are responsible for substantial global morbidity and mortality in young children and elderly individuals. Estimates of the burden of influenza- and RSV-associated hospitalization are limited in Africa.

Methods: We conducted hospital-based surveillance for laboratory-confirmed influenza- and RSV-associated severe acute respiratory illness (SARI) among patients of any age at one hospital and a retrospective review of SARI hospitalizations in five hospitals situated in Antananarivo during 2011-2016.

Evaluating Effectiveness of Mass and Continuous Long-lasting Insecticidal Net Distributions Over Time in Madagascar: A Sentinel Surveillance Based Epidemiological Study.

Background: The reduction of global malaria burden over the past 15 years is much attributed to the expansion of mass distribution campaigns (MDCs) of long-lasting insecticidal nets (LLIN). In Madagascar, two LUN MDCs were implemented and one district also benefited from a community-based continuous distribution (CB-CD). Malaria incidence dropped but eventually rebounded after a decade.

Four years into the Indian ocean field epidemiology training programme.

Introduction: Following the 2005-6 chikungunya outbreak, a project to strengthen regional Public Health preparedness in the Indian Ocean was implemented. It includes the Comoros, Madagascar, Mauritius, Reunion (France) and Seychelles. A Field Epidemiology Training Programme (FETP-OI) was started in 2011 to develop a pool of well-trained intervention epidemiologists.

Pneumonic Plague Transmission, Moramanga, Madagascar, 2015.

During a pneumonic plague outbreak in Moramanga, Madagascar, we identified 4 confirmed, 1 presumptive, and 9 suspected plague case-patients. Human-to-human transmission among close contacts was high (reproductive number 1.44) and the case fatality rate was 71%.

Analysing trends and forecasting malaria epidemics in Madagascar using a sentinel surveillance network: a web-based application.

Background: The use of a malaria early warning system (MEWS) to trigger prompt public health interventions is a key step in adding value to the epidemiological data routinely collected by sentinel surveillance systems.

Methods: This study describes a system using various epidemic thresholds and a forecasting component with the support of new technologies to improve the performance of a sentinel MEWS. Malaria-related data from 21 sentinel sites collected by Short Message Service are automatically analysed to detect malaria trends and malaria outbreak alerts with automated feedback reports.

Modeling of spatio-temporal variation in plague incidence in Madagascar from 1980 to 2007.

Plague is an infectious disease caused by the bacterium Yersinia pestis, which, during the fourteenth century, caused the deaths of an estimated 75-200 million people in Europe. Plague epidemics still occur in Africa, Asia and South America. Madagascar is today one of the most endemic countries, reporting nearly one third of the human cases worldwide from 2004 to 2009.

Has Madagascar lost its exceptional leptospirosis free-like status?

Background: Leptospirosis is a widespread but underreported cause of morbidity and mortality. It has rarely been reported in either humans or animals in Madagascar.

Methods: We conducted a cross-sectional survey of the inhabitants in Moramanga, Madagascar, in June 2011, to estimate the prevalence of human infection using the microscopic agglutination test (MAT).

Surveillance and control of rabies in La Reunion, Mayotte, and Madagascar.

Mayotte and La Reunion islands are currently free of animal rabies and surveillance is performed by the French Human and Veterinary Public Health Services. However, dog rabies is still enzootic in Madagascar with 4 to 10 confirmed human cases each year. The number of antirabies medical centres in Madagascar is still scarce to provide easy access to the local population for post-exposure rabies prophylaxis.

Case-control study of the etiology of infant diarrheal disease in 14 districts in Madagascar.

Background: Acute diarrhea is a major cause of childhood morbidity and mortality worldwide. Its microbiological causes and clinico-epidemiological aspects were examined during the rainy seasons from 2008 to 2009 in 14 districts in Madagascar.

Methods: Stool specimens of 2196 children with acute diarrhea and 496 healthy children were collected in a community setting.

Tuberculin reactivity in first-year schoolchildren in Madagascar.

Objective: The tuberculin skin test (TST) is an important tool in the diagnosis of tuberculosis infection in children. However, the interpretation of TST may be complicated by prior Bacillus Calmette-Guerin (BCG) vaccination. We evaluated the effect of vaccination with BCG on TST reactivity in first-year pupils attending state schools in Antananarivo.

Pandemic influenza A(H1N1) 2009 virus outbreak among boarding school pupils in Madagascar: compliance and adverse effects of prophylactic oseltamivir treatment.

Introduction: In October 2009, the first outbreak of pandemic influenza A(H1N1) 2009 virus  in Madagascar occurred at a school in Antananarivo. Among the first 12 cases, five were reported in boarding pupils at the school. The school closed 10 days into the outbreak.

Variation in gamma interferon responses to different infecting strains of Mycobacterium tuberculosis in acid-fast bacillus smear-positive patients and household contacts in Antananarivo, Madagascar.

The majority of healthy individuals exposed to Mycobacterium tuberculosis will not develop tuberculosis (TB), though many may become latently infected. More precise measurement of the human immune response to M. tuberculosis infection may help us understand this difference and potentially identify those subjects most at risk of developing active disease.

Sentinel surveillance system for early outbreak detection in Madagascar.

Background: Following the outbreak of chikungunya in the Indian Ocean, the Ministry of Health directed the necessary development of an early outbreak detection system. A disease surveillance team including the Institut Pasteur in Madagascar (IPM) was organized to establish a sentinel syndromic-based surveillance system. The system, which was set up in March 2007, transmits patient data on a daily basis from the various voluntary general practitioners throughout the six provinces of the country to the IPM.

Dog ecology and demography in Antananarivo, 2007.

Background: Rabies is a widespread disease in African domestic dogs and a serious public health problem in developing countries. Canine rabies became established in Africa during the 20th century, coinciding with ecologic changes that favored its emergence in canids.This paper reports the results of a cross-sectional study of dog ecology in the Antananarivo urban community in Madagascar.

Seroprevalence of hepatitis C and associated risk factors in urban areas of Antananarivo, Madagascar.

Background: The risk factors for the transmission of HCV vary substantially between countries and geographic regions. The overall prevalence in south and east Africa region has been estimated to be 1.6% but limited information about the epidemiology of HCV infection in Madagascar is available

Methods: A cross-sectional survey for hepatitis C antibodies was conducted in 2,169 subjects of the general population of Antananarivo to determine seroprevalence of hepatitis C and associated risk factors.

Epidemiological trends for human plague in Madagascar during the second half of the 20th century: a survey of 20,900 notified cases.

Objectives: To describe the principal characteristics and epidemiological trends for human plague in modern times based on the largest reported series of cases from the highly active Malagasy focus.

Methods: We used a file of 20,900 notified cases of suspected plague, 4,473 of which were confirmed or probable, to carry out a statistical analysis of incidence and mortality rates and associated factors for 5-year periods from 1957 to 2001.

Results: Our analysis of trends showed (1) an increase in the incidence rate and the number of districts affected, (2) an increase in the proportion of bubonic forms (64.

A simple and convenient microtiter plate assay for the detection of bactericidal antibodies to Vibrio cholerae O1 and Vibrio cholerae O139.

It is believed that the correlate of protection for cholera can be determined by the serum vibriocidal assay. The currently available vibriocidal assays, based on the conventional agar plating technique, are labor intensive. We developed a simple and convenient microtiter plate assay for the detection of vibriocidal antibodies that is equally as efficient for Vibrio cholerae O1 and for V.