Performance of passive case detection for malaria surveillance: results from nine countries in Mesoamerica and the Dominican Republic.

BACKGROUND: In malaria elimination settings, available metrics for malaria surveillance have been insufficient to measure the performance of passive case detection adequately. An indicator for malaria suspected cases with malaria test (MSCT) is proposed to measure the rate of testing on persons presenting to health facilities who satisfy the definition of a suspected malaria case. This metric does not rely on prior knowledge of fever prevalence, seasonality, or external denominators, and can be used to compare detection rates in suspected cases within and between countries, including across settings with different levels of transmission. METHODS: To compute the MSCT, an operational definition for suspected malaria cases was established, including clinical and epidemiological criteria. In general, suspected cases included: (1) persons with fever detected in areas with active malaria transmission; (2) persons with fever identified in areas with no active transmission and travel history to, or residence in areas with active transmission (either national or international); and (3) persons presenting with fever, chills and sweating from any area. Data was collected from 9 countries: Belize, Colombia (in areas with active transmission), Costa Rica, Dominican Republic, El Salvador, Guatemala, Honduras, Nicaragua, and Panama (September-March 2020). A sample of eligible medical records for 2018 was selected from a sample of health facilities in each country. An algorithm was constructed to assess if a malaria test was ordered or performed for cases that met the suspected case definition. RESULTS: A sample of 5873 suspected malaria cases was obtained from 239 health facilities. Except for Nicaragua and Colombia, malaria tests were requested in less than 10% of all cases. More cases were tested in areas with active transmission than areas without cases. Travel history was not systematically recorded in any country. CONCLUSIONS: A statistically comparable, replicable, and standardized metric was proposed to measure suspected malaria cases with a test (microscopy or rapid diagnostic test) that enables assessing the performance of passive case detection. Cross-country findings have important implications for malaria and infectious disease surveillance, which should be promptly addressed as countries progress towards malaria elimination. Local and easy-to-implement tools could be implemented to assess and improve passive case detection.

Continued Sensitivity of Plasmodium falciparum to Artemisinin in Guyana, With Absence of Kelch Propeller Domain Mutant Alleles.

Because of concerns about possible emergence of artemisinin resistance strains of Plasmodium falciparum in mining areas of the interior of Guyana, a 7-day artesunate trial was conducted from March to December 2014. The day-3 parasite clearance rate, the efficacy of artesunate at day 28, and polymorphism of Kelch 13 (PfK13)-the marker of artemisinin resistance-were assessed. The study confirmed the continued sensitivity of P falciparum to artemisinin. A 7-day course of artesunate was 100% efficacious with only 2% (95% confidence interval, .1%-10.9%) of enrolled subjects positive at day 3. All day-0 parasite samples were wild type. Continued resistance monitoring is nevertheless recommended, given the widespread availability and uncontrolled use of artemisinin drugs in mining areas of Guyana.

Malaria vector research and control in Haiti: a systematic review.

BACKGROUND: Haiti has a set a target of eliminating malaria by 2020. However, information on malaria vector research in Haiti is not well known. This paper presents results from a systematic review of the literature on malaria vector research, bionomics and control in Haiti. METHODS: A systematic search of literature published in French, Spanish and English languages was conducted in 2015 using Pubmed (MEDLINE), Google Scholar, EMBASE, JSTOR WHOLIS and Web of Science databases as well other grey literature sources such as USAID, and PAHO. The following search terms were used: malaria, Haiti, Anopheles, and vector control. RESULTS: A total of 132 references were identified with 40 high quality references deemed relevant and included in this review. Six references dealt with mosquito distribution, seven with larval mosquito ecology, 16 with adult mosquito ecology, three with entomological indicators of malaria transmission, eight with insecticide resistance, one with sero-epidemiology and 16 with vector control. In the last 15 years (2000-2015), there have only been four published papers and three-scientific meeting abstracts on entomology for malaria in Haiti. Overall, the general literature on malaria vector research in Haiti is limited and dated. DISCUSSION: Entomological information generated from past studies in Haiti will contribute to the development of strategies to achieve malaria elimination on Hispaniola. However it is of paramount importance that malaria vector research in Haiti is updated to inform decision-making for vector control strategies in support of malaria elimination.

Census-derived migration data as a tool for informing malaria elimination policy.

BACKGROUND: Numerous countries around the world are approaching malaria elimination. Until global eradication is achieved, countries that successfully eliminate the disease will contend with parasite reintroduction through international movement of infected people. Human-mediated parasite mobility is also important within countries near elimination, as it drives parasite flows that affect disease transmission on a subnational scale. METHODS: Movement patterns exhibited in census-based migration data are compared with patterns exhibited in a mobile phone data set from Haiti to quantify how well migration data predict short-term movement patterns. Because short-term movement data were unavailable for Mesoamerica, a logistic regression model fit to migration data from three countries in Mesoamerica is used to predict flows of infected people between subnational administrative units throughout the region. RESULTS: Population flows predicted using census-based migration data correlated strongly with mobile phone-derived movements when used as a measure of relative connectivity. Relative population flows are therefore predicted using census data across Mesoamerica, informing the areas that are likely exporters and importers of infected people. Relative population flows are used to identify community structure, useful for coordinating interventions and elimination efforts to minimize importation risk. Finally, the ability of census microdata inform future intervention planning is discussed in a country-specific setting using Costa Rica as an example. CONCLUSIONS: These results show long-term migration data can effectively predict the relative flows of infected people to direct malaria elimination policy, a particularly relevant result because migration data are generally easier to obtain than short-term movement data such as mobile phone records. Further, predicted relative flows highlight policy-relevant population dynamics, such as major exporters across the region, and Nicaragua and Costa Rica's strong connection by movement of infected people, suggesting close coordination of their elimination efforts. Country-specific applications are discussed as well, such as predicting areas at relatively high risk of importation, which could inform surveillance and treatment strategies.

Malaria in the Americas: trends from 1959 to 2011.

Malaria has declined in recent years in countries of the American continents. In 2011, 12 of 21 endemic countries had already met their 2015 Millennium Development Goal. However, this declining trend has not been adequately evaluated. An analysis of the number of cases per 100,000 people (annual parasite index [API]) and the percentage of positive blood slides (slide positivity rate [SPR]) during the period of 1959-2011 in 21 endemic countries was done using the joinpoint regression methodology. During 1960-1979, API and SPR increased significantly and peaked in the 1980s. Since the 1990s, there have been significant declining trends in both API and SPR. Additionally, both Plasmodium vivax and P. falciparum species-specific incidence have declined. With the exception of two countries, such a collectively declining malaria trend was not observed in previous decades. This presents a unique opportunity for the Americas to seriously consider malaria elimination as a final goal.

Success in controlling a major outbreak of malaria because of Plasmodium falciparum in Jamaica.

In 2006, after 44 years of eradication of malaria, Jamaica had an outbreak of Plasmodium falciparum: 406 confirmed cases between September 2006 and December 2009 with a peak of the epidemic in December 2006. In response to the outbreak, the Ministry of Health launched an emergency response through early detection and prompt treatment of cases, vector control, public education and intersectoral collaboration. Ninety percent (361) of cases were residents of Kingston, and 63.6% were identified through house to house surveillance visits. For 56% of the confirmed cases, treatment with chloroquine was initiated within a week of onset of symptoms. Only one (0.3%) of 358 cases who had a post-treatment smear on day 7 had a persistent asexual parasitaemia, while none of the 149 persons who had a follow-up smear on day 28 was positive. The outbreak highlighted the need for increased institutional capacity for surveillance, confirmation and treatment of malaria as well as effective prevention and control of outbreaks which can occur after elimination. Jamaica appears to have successfully eliminated malaria after its reintroduction.

Percepcion del riesgo, comportamientos riesgosos y seroprevalencia del VIH en trabajadoras sexuales de Georgetown, Guyana / HIV risk perception, risk behavior, and seroprevalence among female commercial sex workers in Georgetown, Guyana

A study of 108 female sex workers engaged in prostitution in Georgetown, Guyana, was made in April 1993. Based on interviews and procurement of blood samples, the study investigated relationships between HIV seroprevalences and AIDS knowledge, risk behaviors, client characteristics, and condom use. Street-walkers-as distinct from sex workers in bars, hotels and Port Georgetown-tended to charge less, be worse off socioeconomically, and have clients who were similiarly disadvantaged; they were therefore classified as belonging to a "lower" socioeconomic stratum, while the other workers were classified as belonging to a "higher" stratum. The overall HIV seroprevalence found among the sex workers was 25 percent (95 percent CI: 17-33 percent). But the 50 subjects in the lower stratum had a relatively high seroprevalence (42 percent, as compared to 10 percent among those in the higher stratum), accounting for 21 of the 27 HIV-seropositive subjects. Reported patterns of client origins (Guyanese or foreign), worker willingness to have sex without a condom, and condom use by clients differed by stratum. Participants in the higher stratum were more disposed to having sex without a condom. The workers' knowledge of what causes AIDS and how HIV is transmitted was low in both strata; substantial numbers of workers said they had contracted a sexually transmitted disease within the past two years or were users of illicit drugs. Condom use is reportedly less common among among Guyanese than foreign clients, suggesting a greater risk of contracting HIV from Guyanese clients or infecting Guyanese clients with it. The HIV seroprevalence among those reporting more than five clients per week was statistically greater among those reporting fewer. HIV seropsitivity was relatively high among the 12 workers whosaid they used cocaine. Overall, the findings supported the view that interventions targeted at female sex workers and their clients should be strengthened-more specifically, that concerted efforts should be made to intensify condom promotion, distribution, and social marketing; to improve STD services that provide treatment and counseling for female sex workers; and to increase educational activities among the workers' Guyanese clients (AU)

Percepción del riesgo, comportamientos riesgosos y seroprevalencia del VIH en trabajadoras sexuales de Georgetown, Guyana / HIV risk perception, risk behavior, and seroprevalence among female commercial sex workers in Georgetown, Guyana

En abril de 1993 se realizó un estudio en 108 trabajadoras sexuales que ejercían la prostitución en Georgetown, Guyana. Mediante entrevistas y pruebas de sangre, se investigaron las relaciones entre la seroprevalencia del VIH y conocimientos sobre el sida, prácticas riesgosas, características de los clientes y uso de condones. Las mujeres que trabajaban en la calle - a diferencia de las que trabajaban en bares, hoteles y Puerto Georgetown - solían cobrar menos, estaban en peor situación socioeconómica y tenían clientes en circunstancias similares; por lo tanto, estas mujeres se clasificaron dentro de un estrato socioeconómico "inferior" y las restantes dentro de uno "superior". La seroprevalencia general del VIH observada en las trabajadoras sexuales fue de 25 por ciento (IC95 por ciento=17 a 33 por ciento). Las 50 mujeres del estrato inferior tuvieron, sin embargo, una seroprevalencia relativamente alta (42 por ciento en comparacaión con 10 por ciento de las del estrato superior) y a ese grupo pertenecían 21 de las 27 mujeres seropositivas al VIH. El origen declarado de los clientes(guyaneses o extranjeros), la disposición de las trabajadoras a tener relaciones sexuales sin condón y el uso de condones por los clientes variaron según el estrato. Las participantes del estrato más alto estaban más dispuestas a tener relaciones sexuales sin condón y en ambos estratos las mujeres sabían poco sobre la causa del sida y la transmisión del VIH. Muchas trabajadoras declararon haber contraído una enfermedad de transmisión sexual (ETS) en los 2 años anteriores o haber consumido drogas ilícitas. Según los datos recogidos, los clientes guyaneses usan condones con menos frecuencia que los extranjeros, fenómeno que implica un mayor riesgo de contraer el VIH por contacto con un guyanés o de transmitirlo a un guyanés. La seroprevalencia del VIH en trabajadoras que dijeron tener solo clientes guyaneses fue estadísticamente mayor que la obsevada en las que declararon que sus clientes eran solo extranjeros. La seroprevalencia del VIH en mujeres que declararon tener más de cinco clientes a la semana fue estadísticamente mayor que en las que tenían menos clientes. La seropositividad al VIH fue relativamente frecuente entre las 12 trabajadoras que declararon haber usado cocaína. En general, los resultados confirman la necesidad de fortalecer las intervenciones dirigidas a las trabajadoras sexuales y a sus clientes

Percepción del riesgo, comportamientos riesgosos y seroprevalencia del VIH en trabajadoras sexuales de Georgetown, Guyana / HIV risk perception, risk behavior, and seroprevalence among female commercial sex workers in Georgetown, Guyana

En abril de 1993 se realizó un estudio en 108 trabajadoras sexuales que ejercían la prostitución en Georgetown, Guyana. Mediante entrevistas y pruebas de sangre, se investigaron las relaciones entre la seroprevalencia del VIH y conocimientos sobre el sida, prácticas riesgosas, características de los clientes y uso de condones. Las mujeres que trabajaban en la calle - a diferencia de las que trabajaban en bares, hoteles y Puerto Georgetown - solían cobrar menos, estaban en peor situación socioeconómica y tenían clientes en circunstancias similares; por lo tanto, estas mujeres se clasificaron dentro de un estrato socioeconómico "inferior" y las restantes dentro de uno "superior". La seroprevalencia general del VIH observada en las trabajadoras sexuales fue de 25 por ciento (IC95 por ciento=17 a 33 por ciento). Las 50 mujeres del estrato inferior tuvieron, sin embargo, una seroprevalencia relativamente alta (42 por ciento en comparacaión con 10 por ciento de las del estrato superior) y a ese grupo pertenecían 21 de las 27 mujeres seropositivas al VIH. El origen declarado de los clientes(guyaneses o extranjeros), la disposición de las trabajadoras a tener relaciones sexuales sin condón y el uso de condones por los clientes variaron según el estrato. Las participantes del estrato más alto estaban más dispuestas a tener relaciones sexuales sin condón y en ambos estratos las mujeres sabían poco sobre la causa del sida y la transmisión del VIH. Muchas trabajadoras declararon haber contraído una enfermedad de transmisión sexual (ETS) en los 2 años anteriores o haber consumido drogas ilícitas. Según los datos recogidos, los clientes guyaneses usan condones con menos frecuencia que los extranjeros, fenómeno que implica un mayor riesgo de contraer el VIH por contacto con un guyanés o de transmitirlo a un guyanés. La seroprevalencia del VIH en trabajadoras que dijeron tener solo clientes guyaneses fue estadísticamente mayor que la obsevada en las que declararon que sus clientes eran solo extranjeros. La seroprevalencia del VIH en mujeres que declararon tener más de cinco clientes a la semana fue estadísticamente mayor que en las que tenían menos clientes. La seropositividad al VIH fue relativamente frecuente entre las 12 trabajadoras que declararon haber usado cocaína. En general, los resultados confirman la necesidad de fortalecer las intervenciones dirigidas a las trabajadoras sexuales y a sus clientes

HIV risk perception, risk behavior, and seroprevalence among female commercial sex workers in Georgetown, Guyana

A study of 108 female sex workers engaged in prostitution in Georgetown, Guyana, was made in April 1993. Based on interviews and procurement of blood samples, the study investigated relationships between HIV seroprevalences and AIDS knowledge, risk behaviors, client characteristics, and condom use. Street-walkers-as distinct from sex workers in bars, hotels, and Port Georgetown-tended to charge less, be worse off socioeconomically, and have clients who were similiarly disadvantaged; they were therefore classified as belonging to a "lower" socioeconomic stratum, while the other workers were classified as belonging to a "higher" stratum. The overall HIV seroprevalence found among the sex workers was 25 percent (95 percent CI: 17 percent-33 percent). But the 50 subjects in the lower stratum had a relatively high seroprevalence (42 percent, as compared to 10 percent among those in higher stratum), accounting for 21 of the 27 HIV-seropositive subjects. Reported patterns of client origins (Guyanese or foreign), worker willingness to have sex without a condom, and condom use by clients differed by stratum. Participants in the higher stratum were more disposed to having sex without a condom. The workers' knowledge of what causes AIDS and how HIV is transmitted was low in both strata; substantial numbers of workers of workers said they had contracted a sexually transmitted disease within the past two years or were users of illicit drugs. Condom use is reportedly less common among Guyanese than foreign clients, suggesting a greater risk of contracting HIV from Guyanese clients or infecting Guyanese clients with it. The HIV seroprevalence among workers who said they had only Guyanese clients was statistically greater than the rate among those who said they had only foreign clients. The HIV seroprevalence among those reporting more than five clients per week was statistically greater than among those reporting fewer. HIV seropisitivity was relatively high among the 12 workers who said they used cocaine. Overall, the findings supported the view that interventions targeted at female sex workers and their clients should be strengthened-more specifically, that concerted efforts should be made to intensify condom promotion, distribution, and social marketing; to improve STD services that provide treatment and counseling for female sex workers; and to increase educational activities among the workers' Guyanese clients (AU)

HIV risk perception, risk behaviour, and seroprevalence among female commercial sex workers in Georgetown, Guyana / Percepción del riesgo, comportamiento de riesgo y seroprevalencia de VIH en trabajadoras sexuales de Georgetown, Guyana

A study of 108 female sex workers engaged in prostitution in Georgetown, Guyana, was made in April 1993. Based on interviews and procurement of blood samples, the study investigated relationships between HIV seroprevalences and AIDS knowledge, risk behaviors, client characteristics, and condom use. Street-walkers­as distinct from sex workers in bars, hotels, and Port Georgetown­tended to charge less, be worse off socioeconomically, and have clients who were similarly disadvantaged; they were therefore classified as belonging to a "lower" socioeconomic stratum, while the other workers were classified as belonging to a "higher" stratum. The overall HIV seroprevalence found among the sex workers was 25% (95%CI: 17%­33%). But the 50 subjects in the lower stratum had a relatively high seroprevalence (42%, as compared to 10% among those in the higher stratum), accounting for 21 of the 27 HIV-seropositive subjects. Reported patterns of client origins (Guyanese or foreign), worker willingness to have sex without a condom, and condom use by clients differed by stratum. Participants in the higher stratum were more disposed to having sex without a condom. The workers' knowledge of what causes AIDS and how HIV is transmitted was low in both strata; substantial numbers of workers said they had contracted a sexually transmitted disease within the past two years or were users of illicit drugs. Condom use is reportedly less common among Guyanese than foreign clients, suggesting a greater risk of contracting HIV from Guyanese clients or infecting Guyanese clients with it. The HIV seroprevalence among workers who said they had only Guyanese clients was statistically greater than the rate among those who said they had only foreign clients. The HIV seroprevalence among those reporting more than five clients per week was statistically greater than among those reporting fewer. HIV seropositivity was relatively high among the 12 workers who said they used cocaine. Overall, the findings supported the view that interventions targeted at female sex workers and their clients should be strengthened­more specifically, that concerted efforts should be made to intensify condom promotion, distribution, and social marketing; to improve STD services that provide treatment and counseling for female sex workers; and to increase educational activities among the workers' Guyanese clients.

En abril de 1993 se llevó a cabo un estudio de 108 trabajadoras sexuales que ejercían la prostitución en Georgetown, Guyana. En el estudio se investigaron, mediante entrevistas y exámenes de sangre, las relaciones entre seroprevalencia de VIH y conocimientos sobre el sida, comportamientos riesgosos, características de los clientes y uso de condones. Las trabajadoras sexuales callejeras ­en contraste con las que trabajaban en bares, hoteles y en Port Georgetown­ por lo general cobraban menos, estaban en peor situación económica y tenían clientes en circunstancias similares. Por lo tanto, se clasificaron como pertenecientes a un estrato socioeconómico más "bajo", mientras que las otras trabajadoras se clasificaron como de estrato más "alto". En todo el grupo de trabajadoras sexuales se encontró una seroprevalencia general de 25% (95%IC: 17%­33%). Las 50 mujeres clasificadas como de estrato bajo tenían una seroprevalencia relativamente alta (42%, comparada con 10% en el estrato alto), y a ese subgrupo pertenecían 21 de las 27 seropositivas a VIH. Según la información dada por las participantes, también se relacionaban con esos estratos el origen de los clientes (guyaneses o extranjeros), el consentimiento a tener relaciones sin condón y el uso de condón por los clientes. Las participantes de estrato alto consentían más a menudo a tener sexo sin condón. Las mujeres de ambos estratos tenían pocos conocimientos acerca de la causa del sida y la transmisión de VIH y un número importante de las trabajadoras declaró haber contraído alguna enfermedad de transmisión sexual o consumido drogas ilegales en los 2 años anteriores. Los clientes guyaneses usan condones menos que los extranjeros, lo que sugiere un riesgo más alto de adquirir VIH de esos clientes y también de infectarlos con el virus. La seroprevalencia de VIH fue más alta entre las trabajadoras que dijeron haber tenido clientes guyaneses que entre las que recibían solamente a clientes extranjeros. Fue además estadísticamente mayor entre las que tenían más de cinco clientes a la semana. La seropositividad a VIH fue relativamente alta entre las 12 trabajadoras que declararon haber usado cocaína. En general, los resultados de este trabajo sustentan el principio de que deben fortalecerse las intervenciones dirigidas a las trabajadoras sexuales y sus clientes. En particular, debe hacerse un esfuerzo para intensificar la promoción, distribución y mercadeo social de los condones; mejorar los servicios de enfermedades de transmisión sexual que ofrecen tratamiento y orientación personal a las trabajadoras sexuales y aumentar las actividades educativas dirigidas a los clientes guyaneses.