[Estimate of the incidence of HIV in the adult population of Paraguay using the MoT mathematical model]. / Estimación de la incidencia de VIH en población adulta de Paraguay con el modelo matemático MoT.

OBJECTIVE: To estimate the incidence of HIV in the adult population of Paraguay for 2014 and analyze its distribution and associated uncertainty according to risk behavior. METHODS The UNAIDS model was applied according to modes of transmission (MoT). Data were obtained from a detailed review of documents prepared between 1996 and 2013. Uncertainty of the estimated values was analyzed. RESULTS: The estimated incidence for 2014 was 0.091% (3,081 new infections). Both the percentage of new infections (74.75%, CI95%: 64.19%-81.47%) and the incidence rate per 10,000 population (9,518) were greater in the group of men who have sex with men (MSM). The second most affected group was made up of those who have stable heterosexual sex (9.9%). Heterosexual transmission accounted for 23% of new cases and 8% corresponded to couples (men and women) who engaged in high-risk behavior for HIV transmission. Female sex workers and intravenous drug users accounted for 1%. CONCLUSIONS: The resulting estimate of the incidence of HIV and its distribution among groups at risk is consistent with national-level reports and with the characteristics of the MSM population, which accounts for the greatest number of cases in the epidemic. Preventive actions should be aimed at this group in order to have a significant impact on the course of the epidemic in the country. Furthermore, it is recommended that preventive activities aimed at stable couples in at-risk groups and the general population be expanded and strengthened.

Estimación de la incidencia de VIH en población adulta de Paraguay con el modelo matemático MoT / Estimate of the incidence of HIV in the adult population of Paraguay using the MoT mathematical model

OBJETIVO: Estimar la incidencia del VIH en la población adulta del Paraguay para 2014, y analizar su distribución con la incertidumbre asociada según comportamiento de riesgo. MÉTODOS: Se aplicó el modelo de ONUSIDA según modos de transmisión (MoT). Los datos se obtuvieron de la revisión detallada de documentos elaborados entre 1996 y 2013. Se realizó el análisis de incertidumbre de los valores estimados. RESULTADOS: La incidencia estimada para 2014 fue 0,091% (3 081 nuevas infecciones). Tanto el porcentaje de nuevas infecciones (74,75%, intervalo de confianza de 95%: 64,19-81,47) como la tasa de incidencia por 10 000 personas (9 518) fueron mayores en el grupo de hombres que tienen sexo con hombres (HSH) y el segundo grupo más afectado fue el de personas que tienen sexo heterosexual estable (9,9%). La transmisión heterosexual se produjo en 23% de nuevos casos y 8% de ellos corresponde a parejas (hombres y mujeres) de personas con comportamiento de alto riesgo de transmisión del VIH. El 1% está relacionado con el trabajo sexual de mujeres y el uso de drogas inyectables. CONCLUSIONES: Los resultados de la estimación de la incidencia de VIH y su distribución entre los grupos en riesgo son congruentes con los de los informes a escala nacional y con la población de HSH, la que acumula más casos de la epidemia. Las acciones de prevención deben dirigirse a este grupo para producir un impacto importante en el curso de la epidemia en el país. Además, se recomienda ampliar y fortalecer las actividades preventivas en las parejas estables de grupos en riesgo y en la población general.

OBJECTIVE: To estimate the incidence of HIV in the adult population of Paraguay for 2014 and analyze its distribution and associated uncertainty according to risk behavior. METHODS The UNAIDS model was applied according to modes of transmission (MoT). Data were obtained from a detailed review of documents prepared between 1996 and 2013. Uncertainty of the estimated values was analyzed. RESULTS: The estimated incidence for 2014 was 0.091% (3,081 new infections). Both the percentage of new infections (74.75%, CI95%: 64.19%-81.47%) and the incidence rate per 10,000 population (9,518) were greater in the group of men who have sex with men (MSM). The second most affected group was made up of those who have stable heterosexual sex (9.9%). Heterosexual transmission accounted for 23% of new cases and 8% corresponded to couples (men and women) who engaged in high-risk behavior for HIV transmission. Female sex workers and intravenous drug users accounted for 1%. CONCLUSIONS: The resulting estimate of the incidence of HIV and its distribution among groups at risk is consistent with national-level reports and with the characteristics of the MSM population, which accounts for the greatest number of cases in the epidemic. Preventive actions should be aimed at this group in order to have a significant impact on the course of the epidemic in the country. Furthermore, it is recommended that preventive activities aimed at stable couples in at-risk groups and the general population be expanded and strengthened.

Estimating HIV incidence from case-report data: method and an application in Colombia.

OBJECTIVE: Quantifying HIV incidence is essential for tracking epidemics but doing this in concentrated epidemic can be a particular challenge because of limited consistent high-quality data about the size, behaviour and prevalence of HIV among key populations. Here, we examine a method for estimating HIV incidence from routinely collected case-reporting data. METHODS: A flexible model of HIV infection, diagnosis and survival is constructed and fit to time-series data on the number of reported cases in a Bayesian framework. The time trend in the hazard of infection is specified by a penalized B-spline. We examine the performance of the model by applying it to synthetic data and determining whether the method is capable of recovering the input incidence trend. We then apply the method to real data from Colombia and compare our estimates of incidence with those that have been derived using alternative methods. RESULTS: The method can feasibly be applied and it successfully recovered a range of incidence trajectories in synthetic data experiments. However, estimates for incidence in the recent past are highly uncertain. When applied to data from Colombia, a credible trajectory of incidence is generated which indicates a much lower historic level of HIV incidence than has previously been estimated using other methods. CONCLUSION: It is feasible, though not satisfactory, to estimate incidence using case-report data in settings with good data availability. Future work should examine the impact on missing or biased data, the utility of alternative formulations of flexible functions specifying incidence trends, and the benefit of also including data on deaths and programme indicators such as the numbers receiving antiretroviral therapy.

Outbreak of Rocky Mountain spotted fever in Córdoba, Colombia.

Rocky Mountain spotted fever (RMSF) is a tick-borne disease caused by the obligate intracellular bacterium Rickettsia rickettsii. Although RMSF was first reported in Colombia in 1937, it remains a neglected disease. Herein, we describe the investigation of a large cluster of cases of spotted fever rickettsiosis in a new area of Colombia.

Outbreak of Rocky Mountain spotted fever in Córdoba, Colombia

Rocky Mountain spotted fever (RMSF) is a tick-borne disease caused by the obligate intracellular bacterium Rickettsia rickettsii. Although RMSF was first reported in Colombia in 1937, it remains a neglected disease. Herein, we describe the investigation of a large cluster of cases of spotted fever rickettsiosis in a new area of Colombia.

A survey of antibodies against Rickettsia rickettsii and Ehrlichia chafeensis in domestic animals from a rural area of Colombia.

In a rural area of Colombia endemic for Rocky Mountain spotted fever, we performed indirect immunofluorescent antibody assays for Rickettsia spp. and Ehrlichia spp. using sera from randomly sampled dogs and horses to test the use of domestic animals as possible sentinels. Antibodies against Ehrlichia spp. were detected in 8 dogs (31.8%). Antibody titers against Rickettsia rickettsii antigen were positive in 4 dogs (18.2%) and 26 horses (16.3%). These values, albeit not directly comparable, are lower than those previously reported for humans in this region. A systemic approach to understanding dynamics of transmission is needed before implementing the use of domestic animals for disease surveillance activities.