GPS Tracking of Free-Ranging Pigs to Evaluate Ring Strategies for the Control of Cysticercosis/Taeniasis in Peru

Background Taenia solium, a parasitic cestode that affects humans and pigs, is the leading cause of preventable epilepsy in the developing world. T. solium eggs are released into the environment through the stool of humans infected with an adult intestinal tapeworm (a condition called taeniasis), and cause cysticercosis when ingested by pigs or other humans. A control strategy to intervene within high-risk foci in endemic communities has been proposed as an alternative to mass antihelminthic treatment. In this ring strategy, antihelminthic treatment is targeted to humans and pigs residing within a 100 meter radius of a pig heavily-infected with cysticercosis. Our aim was to describe the roaming ranges of pigs in this region, and to evaluate whether the 100 meter radius rings encompass areas where risk factors for T. solium transmission, such as open human defecation and dense pig activity, are concentrated. Methodology/Principal Findings In this study, we used Global Positioning System (GPS) devices to track pig roaming ranges in two rural villages of northern Peru. We selected 41 pigs from two villages to participate in a 48-hour tracking period. Additionally, we surveyed all households to record the locations of open human defecation areas. We found that pigs spent a median of 82.8% (IQR: 73.5, 94.4) of their time roaming within 100 meters of their homes. The size of home ranges varied significantly by pig age, and 93% of the total time spent interacting with open human defecation areas occurred within 100 meters of pig residences. Conclusions/Significance These results indicate that 100 meter radius rings around heavily-infected pigs adequately capture the average pig’s roaming area (i.e., home range) and represent an area where the great majority of exposure to human feces occurs

SEROPREVALENCIA DE LA CISTICERCOSIS PORCINA EN TRES CASERÍOS DE LA PROVINCIA DE ANDAHUAYLAS, APURÍMAC

La cisticercosis porcina es endémica en comunidades rurales del Perú debido a la existencia de factores que favorecen la presencia, transmisión y mantenimiento de la enfermedad. El presente trabajo evaluó la prevalencia real de la cisticercosis porcina en tres caseríos (Nueva Esperanza, Turpo y Matapuquio) de la provincia de Andahuaylas, Apurímac. Se muestreó a la totalidad de la población porcina (n=304), exceptuando animales menores de 2 meses y hembras en gestación avanzada. Los sueros se analizaron mediante la prueba de Electro Inmuno Transferencia Blot (EITB). Los datos se analizaron para determinar factores de riesgo y se emplearon en el entorno de una simulación estocástica para estimar la prevalencia real usando funciones de generación de números aleatorios que seguían distribuciones beta-binomiales. El nivel de infección en Nueva Esperanza fue significativamente menor a los encontrados en Turpo y Matapuquio (p<0.05). No hubo diferencias entre sexos, pero se encontró una correlación directa perfecta (rs=1) entre la edad de los animales y la prevalencia de cisticercosis. El análisis de regresión logística mostró que las variables zona de muestreo y edad representaron factores de riesgo asociados a la enfermedad (p<0.0001). Los resultados serológicos indicaron que el porcentaje de prevalencia general fue de 47.3 + 5.6% mientras que las prevalencias para Nueva Esperanza, Turpo y Matapuquio fueron de 26.5, 72.3 y 54.0%, respectivamente. La prevalencia real para los tres caseríos fue del 23%, encontrándose el 96% de las observaciones entre el 17 al 29%. Se concluye que la cisticercosis porcina en los caseríos estudiados es un problema de salud pública.Porcine cysticercosis is endemic in rural communities of Peru, due to prevaling conditions contributing to the occurrence, transmission and maintenance of the disease. This paper assessed the real prevalence of porcine cysticercosis in three villages of Andahuaylas province, Apurímac. All pigs in the area were sampled with the exception of suckling piglets and advanced pregnant sows (n = 304). The samples were analyzed by the Enzyme Immuno Electro Transfer Blot (EITB) test. Resulting data was evaluated to determine the risk factors and a stocastic simulation was used to asses the real prevalence, using functions that generate random numbers that followed beta binomial distributions. The level of infection in Nueva Esperanza was significantly lower to those found in Turpo and Matapuquio (p<0.05). No statistical differences were found due to sex. There was a perfect direct correlation between age and the prevalence of porcine cysticercosis (rs=1). The logistic regression showed that location and age represented risk factors asociated with the disease (p<0.0001). Serologic results indicated that the general prevalence was 47.3 ± 5.6%, while prevalence for Nueva Esperanza was 26.5 ± 7.6, for Turpo was 72.3 ± 9.5, and for Matapuquio was 54.0 ± 10.5%. The real prevalence for all three villages would be of 23%, whereas 96% of the observations were between 17 and 29%. It is concluded that porcine cysticercosis in Andahuaylas villages is a public health proble

INCIDENCIA DE CISTICERCOSIS PORCINA EN EL DISTRITO DE MATAPALO, TUMBES

Se evaluó la prevalencia y la tasa de infección o la fuerza de morbilidad de la cisticercosis expresada como incidencia acumulada en el periodo de enero a abril del 2000 en la población porcina del distrito de Matapalo (Zarumilla, Tumbes). En el primer muestreo se evaluaron 922 cerdos mayores de 3 meses (con excepción de hembras en gestación avanzada), encontrándose una prevalencia del 30.8 ± 3.0%. En el segundo muestreo se evaluaron 778 cerdos, encontrándose una prevalencia de 20.8 ± 2.9%. Un total de 314 animales negativos al primer muestreo fueron evaluados en el segundo muestreo y 36 seroconvirtieron a la prueba de EITB, lo que resultó en una incidencia acumulada de 11.5 ± 3.5%. Se analizaron factores de exposición para la prevalencia de la cisticercosis porcina encontrándose que las variables caserío, edad y muestreo representaron un factor de riesgo para encontrar un animal positivo. Con respecto a la incidencia, se encontró que las variables caserío, edad, condición inmunológica de la madre y sexo representaron un factor de riesgo para contraer la enfermedad.It was evaluated the prevalence and the incidence rate (force of morbidity of cysticercosis) in the period of January-April, 2000 in the porcine population of Matapalo’s village (Zarumilla, Tumbes). In the first sampling, 922 animals older than 3 months were evaluated and 284 resulted positive representing a prevalence of 30.8 ± 3.0% . The second sampling, carried out three months later on 778 animals reported a prevalence of 20.8 ± 2.9%. A total of 314 negative animals at the first sampling were evaluated in the second sampling and 36 seroconverted to the EITB test resulting in an accumulated incidence of 11.5 ± 3.5%. A number of risk factors were analyzed for the prevalence of porcine cysticercosis finding out that village, age and sampling represented a factor of risk to find a positive animal. Similarly, several factors relating to incidence were analized and was found that the variables village, age, immunological condition of the mother, and sex represented risk factors to get the disease

Interspecies interactions and potential Influenza A virus risk in small swine farms in Peru

<p>Abstract</p> <p>Background</p> <p>The recent avian influenza epidemic in Asia and the H1N1 pandemic demonstrated that influenza A viruses pose a threat to global public health. The animal origins of the viruses confirmed the potential for interspecies transmission. Swine are hypothesized to be prime "mixing vessels" due to the dual receptivity of their trachea to human and avian strains. Additionally, avian and human influenza viruses have previously been isolated in swine. Therefore, understanding interspecies contact on smallholder swine farms and its potential role in the transmission of pathogens such as influenza virus is very important.</p> <p>Methods</p> <p>This qualitative study aimed to determine swine-associated interspecies contacts in two coastal areas of Peru. Direct observations were conducted at both small-scale confined and low-investment swine farms (n = 36) and in open areas where swine freely range during the day (n = 4). Interviews were also conducted with key stakeholders in swine farming.</p> <p>Results</p> <p>In both locations, the intermingling of swine and domestic birds was common. An unexpected contact with avian species was that swine were fed poultry mortality in 6/20 of the farms in Chancay. Human-swine contacts were common, with a higher frequency on the confined farms. Mixed farming of swine with chickens or ducks was observed in 36% of all farms. Human-avian interactions were less frequent overall. Use of adequate biosecurity and hygiene practices by farmers was suboptimal at both locations.</p> <p>Conclusions</p> <p>Close human-animal interaction, frequent interspecies contacts and suboptimal biosecurity and hygiene practices pose significant risks of interspecies influenza virus transmission. Farmers in small-scale swine production systems constitute a high-risk population and need to be recognized as key in preventing interspecies pathogen transfer. A two-pronged prevention approach, which offers educational activities for swine farmers about sound hygiene and biosecurity practices and guidelines and education for poultry farmers about alternative approaches for processing poultry mortality, is recommended. Virological and serological surveillance for influenza viruses will also be critical for these human and animal populations.</p

Seroprevalencia de cisticercosis porcina en las villas de Nueva Esperanza, Matapuquio y Turpo en la provincia de Andahuaylas, departamento de Apurímac

La cisticercosis porcina es endémica en comunidades rurales del Perú debido a la existencia de factores que favorecen la presencia, transmisión y mantenimiento de la enfermedad. La presente tesis evaluó la prevalencia real de la cisticercosis porcina en tres villas de la provincia de Andahuaylas – departamento de Apurímac. En estas villas se muestreó a la totalidad de la población porcina (N=304), exceptuando animales menores de 2 meses y hembras preñadas. Las muestras fueron evaluadas mediante la prueba de Ensayo de Blot de Electro Inmuno Transferencia (EITB) o Westernblot. Los datos se analizaron para determinar factores de riesgo y se emplearon en el entorno de una simulación estocástica para estimar la prevalencia real. La simulación estocástica para estimar prevalencia real empleó funciones de generación de números aleatorios que seguían distribuciones beta – binomiales. La simulación se implementó en el entorno de una hoja de cálculo Excel 2000® (Microsoft), mientras que las funciones se implementaron empleando el paquete comercial de simulación @Risk 4.0® (Palisade Corp.). El nivel de infección en Nueva Esperanza, fue significativamente menor a los encontrados en Turpo y Matapuquio (p<0.05), se halló además, una mayor proporción de animales machos infectados, pero no estadísticamente significativo. Respecto a la edad se encontró una correlación directa perfecta (rs=1) entre edad de los animales y prevalencia de cisticercosis. El análisis de regresión logística mostró que las variables zona de muestreo y edad representan factores de riesgo asociados a la enfermedad (p<0.0001), siguiendo el mismo criterio se observó que la probabilidad de encontrar un animal afectado por cisticercosis es mayor cuando la edad de los mismos aumenta. De acuerdo a los resultados serológicos la tasa de prevalencia general fue de 47.3±5.6 mientras que las prevalencias para cada villa fueron de 26.5±7.6 para Nueva Esperanza, 72.3±9.5 para Turpo y 54.0±10.5 para Matapuquio. En base a los resultados de la simulación, se encontró que la prevalencia real para las tres villas en estudio sería del 23% y que el 96% de las observaciones se encontrarían en el intervalo 17% al 29%. Se concluye que la cisticercosis porcina en las villas de la provincia de Andahuaylas es un problema de salud pública.Porcine cysticercosis is endemic in rural communities of Peru, due to the conditions that contribute to its onset, transmission and maintenance. This thesis assessed the real prevalence of porcine cysticercosis in three villages of Andahuaylas province, Apurimac Department. The entire porcine population was sampled (N = 304), except for suckling piglets under 2 months old and pregnant sows. The samples were examinee by the Enzyme Immuno Electro Transfer Blot (EITB) test. Resulting data was analyzed to determine the risk factors and was analyzed in a stocastic simulation to asses the real prevalence. This stocastic simulation used random numbers generation functions that followed beta binomial distributions. This simulation was implemented in Microsoft Excel 2000® while the functions were implemented using the commercial simulation software @Risk 4.0® from Palisade Corp. the infection level in Nueva Esperanza was significantly lower to those founded in Turpo and Matapuquio (p<0.05), it was also found that a bigger proportion of male pig infected, but it was not estatistically significant. In what respects to the age, a perfectly direct correlation was found between the animals age and the porcine cysticercosis prevalence. The logistic regression showed that the variables sampling location and age represent risk factors asociated with the disease (p<0.0001). Following the same criterion it was observed that the chance to find an cysticercotic pig is higher when the age of the pig raises. According to the serologic sampling results, the general prevalence ratio was 47.3±5.6 while the prevalences for each village were 26.5±7.6 for Nueva Esperanza, 72.3±9.5 for Turpo and 54.0±10.5 for Matapuquio. In what respects to in the simulation results, it was found that the real prevalence for the three villages under study would be of 23% and that the 96% of the happenings would be inside the 17% and 29% interval. It is concluded then that, porcine cysticercosis in the Andahuaylas’ villages is a public health problem.Tesi

Spatial Relationship Between \u3ci\u3eTaenia Solium\u3c/i\u3e Tapeworm Carriers and Necropsy Cyst Burden in Pigs

Background Taenia solium, a parasite that affects humans and pigs, is the leading cause of preventable epilepsy in the developing world. Geographic hotspots of pigs testing positive for serologic markers of T. solium exposure have been observed surrounding the locations of human tapeworm carriers. This clustered pattern of seropositivity in endemic areas formed the basis for geographically targeted control interventions, which have been effective at reducing transmission. In this study, we further explore the spatial relationship between human tapeworm carriers and infected pigs using necroscopic examination as a quantitative goldstandard diagnostic to detect viable T. solium cyst infection in pigs. Methodology/Principal findings We performed necroscopic examinations on pigs from 7 villages in northern Peru to determine the number of viable T. solium cysts in each pig. Participating humans in the study villages were tested for T. solium tapeworm infection (i.e., taeniasis) with an ELISA coproantigen assay, and the distances from each pig to its nearest human tapeworm carrier were calculated. We assessed the relationship between proximity to a tapeworm carrier and the prevalence of light, moderate, and heavy cyst burden in pigs. The prevalence of pig infection was greatest within 50 meters of a tapeworm carrier and decreased monotonically as distance increased. Pigs living less than 50 meters from a human tapeworm carrier were 4.6 times more likely to be infected with at least one cyst than more distant pigs. Heavier cyst burdens, however, were not more strongly associated with proximity to tapeworm carriers than light cyst burdens. Conclusion/Significance Our study shows that human tapeworm carriers and pigs with viable T. solium cyst infection are geographically correlated in endemic areas. This finding supports control strategies that treat humans and pigs based on their proximity to other infected individuals. We did not, however, find sufficient evidence that heavier cyst burdens in pigs would serve as improved targets for geographically focused control interventions