Lutzomyia longipalpis (Diptera: Psychodidae) Argentina-Bolivia border: new report and genetic diversity

American visceral leishmaniasis (AVL) has two main scenarios of transmission as follows: scattered cases in rural areas and urban outbreaks. Urban AVL is in active dispersion from the northeastern border of Argentina-Paraguay-Brazil to the South. The presence of Lutzomyia longipalpis was initially reported in urban environments in the northwestern border of the country. The presence of Lu. longipalpis, environmental variables associated with its distribution, and its genetic diversity were assessed in Salvador Mazza, Argentina, on the border with Bolivia. The genetic analysis showed high haplotype diversity, low nucleotide diversity, and low nucleotide polymorphism index. We discuss the hypothesis of an expanding urban population with introgressive hybridisation of older haplogroups found in their path in natural forest or rural environments, acquiring a new adaptability to urban environments, and the possibility of changes in vector capacity.

Prevalencia de infección por Trypanosoma cruzi en escolares de Salta y Chaco, Argentina / Seroprevalencia of Trypanosoma cruzi infection in school-age children from localities in Salta and Chaco, Argentina / Prevalência de infecção por Trypanosoma cruzi em crianças em idade escolar de Salta e Chaco, na Argentina

El objetivo del trabajo consistió en identificar la seroprevalencia de la infección por Trypanosoma cruzi en niños en edad escolar en localidades de las provincias de Salta y Chaco. Se trabajó en 44 escuelas de la ciudad de Salta, en parajes de San Carlos; en 10 escuelas de La Unión y en 7 escuelas de Taco Pozo. El trabajo tiene un diseño de corte transversal. La toma de muestra se realizó por punción capilar con equipos Serokit, y la confirmación de los casos seropositivos o dudosos por punción venosa, y obtención de suero, para realizar HAI y ELISA. Los casos seropositivos confirmados fueron tratados con Benznidazol® durante 60 días en dosis de 5-7mg/kg/ día. Para el análisis estadístico se elaboraron tablas con frecuencias absolutas y relativas. Se analizaron 17.884 escolares y se detectaron159 seropositivos, siendo la mayor seroprevalencia en la localidad de La Unión y la menor en la ciudad de Salta. Se aplicó tratamiento a 93 niños (71,54 %) de la ciudad y en el ámbito rural se trataron todos los casos. La vía de infección vectorial fue la de mayor predominio en las madres (64,47%). Se concluye que aunque la seroprevalencia fue menor en la ciudad de Salta que en las zonas rurales, es necesario continuar con la vigilancia.

The aim of this work was to identify seroprevalence of Trypanosoma cruzi infection in school-age children who live in localities from Salta and Chaco. This work was conducted in the following schools: 44 located in Salta city, 10 in La Unión, 7 in Taco Pozo, and several in rural spots around San Carlos town. The design was cross-sectional and the samples were taken by capillary punction with Serokit equipment. Seropositive cases were confirmed by HAI and ELISA performed on serum obtained by venous punction. Confirmed seropositive cases were treated with Benznidazol® for 60 days in doses of 5-7 mg/kg/day. Tables with absolute and relative frequencies were made for statistical analysis. It resulted that the number of school-aged children analyzed was 17,884, 159 being seropositive. The highest seroprevalence was detected in La Unión and the lowest in Salta city. Treatment was given to 93 children (71.54%) from Salta city, while every child was treated in rural areas. Infections in mothers was vector-borne mainly (64.47%). It can be concluded that even though seroprevalence was lower in the city of Salta than in rural areas, it is important to continue monitoring for Chagas disease.

O objetivo do trabalho consistiu em identificar a soroprevalência da infecção por Trypanosoma cruzi em crianças em idade escolar em localidades das províncias de Salta e de Chaco. O trabalho foi realizado em 44 escolas da cidade de Salta, em paragens de San Carlos; em 10 escolas de La Unión e em 7 escolas de Taco Pozo. O mesmo tem um desenho de corte transversal. Tomada de amostra: foi realizada por punção capilar com equipamentos Serokit e a confirmação dos casos soropositivos ou duvidoso por punção venosa e obtenção de soro, para realizar HAI e ELISA. Os casos soropositivos confirmados foram tratados com Benznidazole® durante 60 dias em doses de 5-7 mg/kg/dia. Para a análise estatística foram preparadas tabelas com frequências absolutas e relativas. Analisaram-se 17.884 crianças detectando 159 soropositivos, sendo a maior soroprevalência na cidade de La Unión e a menor na cidade de Salta. Aplicou-se o tratamento a 93 crianças, (71,54%) da cidade e na área rural se trataram todos os casos. A via de infecção vetorial foi a de maior predominância nas mães (64,47%). Conclui-se que embora a soroprevalência tenha sido menor na cidade de Salta do que nas áreas rurais, é necessário continuar com a vigilância.

Diagnóstico de infección por Trypanosoma cruzi en Centros de Atención Primaria de Salta, Argentina / Diagnosis of Trypanosoma cruzi infection in Primary Public Health Centers of Salta, Argentina / Diagnóstico de infecção por Trypanosoma cruzi nos Postos de Saúde de Salta, Argentina

La Enfermedad de Chagas causada por el parásito hemoflagelado Trypanosoma cruzi, constituye un grave problema de Salud Pública. En Argentina, se controla sistemáticamente la sangre a transfundir, la donación de órganos y se ha disminuido notablemente la transmisión vectorial. El objetivo de este proyecto fue implementar el uso del equipo para recolección de sangre capilar y conservación en glicerina (Serokit) en los servicios de enfermería de los Centros de Atención Primaria de la Salud en la ciudad de Salta a fin de conocer la seroprevalencia de infección por Trypanosoma cruzi en pacientes que concurren a los mismos. Para ello se realizó el par serológico HAI y ELISA en las muestras conservadas en Serokit y luego en muestras de sangre tomadas por punción venosa para confirmación. Durante dos años de trabajo se analizaron 1647 pacientes que concurrieron a 28 Centros de Salud, resultando 1,7% (29/1647) seropositivos. El Valor Predictivo Positivo fue 93,50% y el Valor Predictivo Negativo fue 99,8%. Todos los niños seropositivos fueron tratados con Benznidazol. Se concluye que el uso de Serokit para la toma y conservación de muestras para posterior diagnóstico de infección por Trypanosoma cruzi es recomendable en Centros de Atención Primaria de la Salud que no cuentan con laboratorio.

Chagas disease is caused by the hemoflagelate parasite Trypanosoma cruzi, and represents a main concern in public health. In Argentina, blood transfusion and organ donation are systematically controlled for T. cruzi infection, and vectorial transmission has dropped significantly. The aim of this project was to implement the use of the equipment for collecting capillary blood and conservation in glycerine (Serokit) in the nursery service of Primary Health Care Centers (PHCC) in the city of Salta, and to know the seroprevalence of T. cruzi infection in PHCC patients. To that aim, the serological pair HAI and ELISA was carried out in samples preserved in Serokit, followed by analysis of blood samples taken by venous punction to confirm the results. During a two-year period, 1647 patients that were assisted at 28 PCHC were analyzed, resulting in 1.7% (29/1647) seropositive samples. Positive Predictive Value was 93.5% and Negative Predictive Value was 99.8%. Every seropositive child was given Benznidazole treatment. It can be concluded that use of Serokit for taking and preserving samples to diagnose serologically T. cruzi infection is recommended in PHCC that lack their own biochemistry laboratory.

A doença de Chagas produzida pelo protozoário flagelado Trypanosoma cruzi constitui um grave problema para a Saúde Pública. Na Argentina, o controle sistemático do sangue para transfusão e o do órgão para transplantar, fez com que diminuísse notavelmente a transmissão vetorial. O objetivo deste projeto foi implementar o uso do equipamento para coleta de sangue capilar e conservação em glicerina (Serokit) nos serviços de enfermagem dos Postos de Atenção Primaria da Saúde da cidade de Salta a fim de conhecer a soroprevalência de infecção com Trypanosoma cruzi em pacientes que são atendidos nos mesmos. Foi realizado o par sorológico HAI e ELISA nas amostras conservadas em Serokit e depois nas amostras de sangue retiradas através de uma punção venosa para a confirmação. Durante dois anos de trabalho, foram analisados 1647 pacientes que foram atendidos nos 28 Postos de Saúde, resultando 1.7% (29/1647) soropositivos. O Valor Preditivo Positivo foi Tripae 93.50% e o Valor Preditivo Negativo foi de 99.8%. Todas as crianças soropositivas foram medicadas com Benznidazol. A conclusão é que o uso de Serokit para a tomada e conservação de amostras para posterior diagnóstico de infecção por Trypanosoma cruzi é recomendável nos Postos de Atenção Primária da Saúde onde não existe a disponibilidade de laboratórios.

Oviposición diaria de Aedes aegypti en Orán, Salta, Argentina / Daily oviposition activity of Aedes aegypti in Orán, Argentina / Oviposição diária de Aedes aegypti em Orán, Salta (Argentina)

El objetivo del estudio fue determinar los horarios de máxima actividad de oviposición de Aedes aegypti en la ciudad de Orán (noroeste argentino). Se realizaron muestreos quincenales entre noviembre de 2006 y febrero de 2007 (primavera-verano). La ciudad fue dividida en tres zonas (norte, centro, sur), donde fueron seleccionadas al azar las viviendas para colocar dos ovitrampas en el exterior de las mismas. Las ovitrampas fueron reemplazadas cada cuatro horas, desde la mañana (8h) hasta el atardecer (20h). Se registró la mayor cantidad de huevos entre las 16 y 20 h (81 por ciento). Estos datos aportan al conocimiento del vector y, por lo tanto, de la posibilidad de control, pudiendo realizarse las fumigaciones en la franja horaria con mayor actividad de oviposición.

The study aimed to determinate the maximum daily peak of Aedes aegypti oviposition in the city of Oran, northwestern Argentina. Biweekly samplings were taken between November 2006 and February 2007 (spring-summer). The city was divided into three areas (north, center, and south) and households were randomly selected. Two ovitraps were placed outdoors in the selected houses. Ovitraps were replaced every four hours, from morning (8 a.m.) to late afternoon (8 p.m.). The largest number of eggs was recorded between 4 p.m. and 8 p.m. (81 percent). These findings enhance our understanding of the vector and thus its control such as spraying during the hours of peak oviposition activity.

O objetivo do estudo foi determinar os horários de máxima atividade de oviposição de Aedes aegypti na cidade de Orán (noroeste argentino). Foram realizadas coletas quinzenais, entre novembro de 2006 e fevereiro de 2007 (primavera-verão). A cidade foi dividida em três zonas (norte, centro, sul); foram escolhidos aleatoriamente dez domicílios em cada zona e duas ovitrampas foram instaladas no exterior de cada domicílio. As ovitrampas eram trocadas a cada quatro horas, cobrindo desde a manhã (8h) até a noite (20h). A maior quantidade de ovos (81 por cento) foi registrada entre as 16h e 20h. Esses dados aportam conhecimento do vetor e, portanto, a seu controle, como, por exemplo, realizar a fumegação na faixa horária de maior atividade de oviposição.

Urban distribution of Phlebotominae in a cutaneous leishmaniasis focus, Argentina

Urbanization and vector domestication are currently proposed as factors that contributed to the recent increase of American cutaneous leishmaniasis (ACL). Is likely also urban transmission? Oran is the main city in the Argentinean hyper-endemic area of ACL, and human cases in urban residences are usually reported. In order to assess the spatial distribution of risk, phlebotomine traps were located in different environments of Oran. A total of 7,787 sand flies were captured: Lutzomyia neivai (98.1 percent), Lutzomyia migonei (1.2 percent), Lutzomyia cortelezzii (0.7 percent), and one Lutzomyia shannoni. During the season of transmission (April-May) a single sand fly was obtained in one out of five urban sites, while a trap in a peri-urban pigsty captured up to 2,985 Lu. neivai/night. Captures performed in the other season of vector activity (September-October) revealed that small-scale changes in the pigsty environment resulted in noticeable changes in the abundance of Lu. neivai. In addition, in a new neighbourhood, on the fringe of the city, 1,073 Lu. neivai/site were captured in the forested edge but one in the yard of the houses. Therefore, in this urban ACL focus the human-vector effective contact risk is still associated with peri-urban vegetation and ecotone modifications despite the urban residence of the cases.

Distribución espacial de Anopheles pseudopunctipennis en las Yungas de Salta, Argentina / Spatial distribution of Anopheles pseudopunctipennis in the Yungas de Salta rainforest, Argentina

OBJETIVO: Comparar la abundancia de Anopheles pseudopunctipennis, y otros anofelinos, en tres zonas silvestres y modificadas por el hombre, a fin de verificar en qué medida tales diferencias ambientales afectan la distribución espacial de estos mosquitos. MÉTODOS: Se realizaron muestreos mensuales (diciembre de 2001 a diciembre de 2002), con trampas de luz CDC con CO2, en cada sitio de muestreo (selva, borde de selva y peridomicilio). En el peridomicilio, además, dos operadores aspiraron mosquitos posados sobre las paredes. Se estimaron índices de diversidad y abundancia de especies, y se intentó caracterizar a los ambientes estudiados mediante ANOVA, cálculo de cosenos y análisis de agrupamientos. RESULTADOS: Anopheles pseudopunctipennis fue la especie más abundante. Se colectaron también An. argyritarsis, An. nuneztovari, An. rangeli y An. strodei. Excepto An. nuneztovari que no se capturó en el peridomicilio, las demás se colectaron en los tres ambientes. No hubo diferencias en los índices de diversidad, ni tampoco entre los ambientes estudiados; sin embargo, el análisis de agrupamiento separó el borde de la selva, donde todas las especies fueron más abundantes en general. CONCLUSIONES: El borde de la selva fue el ambiente que presentó la mayor abundancia, representando, además del peridomicilio, un ambiente de alto riesgo para la transmisión del paludismo.

American cutaneous leishmaniasis outbreak, Tartagal city, province of Salta, Argentina, 1993

An American cutaneous leishmaniasis outbreak, with cases clustering during 1993 in Tartagal city, Salta, was reported. The outbreak involved 102 individuals, 43.1 percent of them with multiple ulcers. Age (mean: 33 years old) and sex distribution of cases (74.5 percent males), as well as working activity (70 forest-related), support the hypothesis of classical forest transmission leishmaniasis, despite the fact that the place of permanent residence was in periurban Tartagal. Moreover, during July, sandflies were only collected from one of the 'deforestation areas'. Lutzomyia intermedia was the single species of the 491 phlebotomines captured, reinforcing the vector incrimination of this species. Most infections must have been acquired during the fall (April to June), a pattern consistent with previous sandfly population dynamics data. Based on the epidemiological and entomological results, it was advised not to do any vector-targeted periurban control measures during July. Further studies should be done to assess if the high rate of multiple lesions was due to parasite factors or to infective vector density factors

La enfermedade de Chagas congenita en la Provincia de Salta, Argentina, años 1980-1997 / Congenital Chagas' disease in the Province of Salta, Argentina, from 1980 to 1997

Se presenta la experiencia de 18 años en la provincia de Salta en el manejo de recién nacidos con enfermedad de Chagas congénita. Desde distintos ámbitos del sistema provincial de salud, el Hospital Materno-infantil de la ciudad de Salta, hospitales del interior y la atención ambulatoria se detectaron y diagnosticaron 102 recién nacidos (RN) y lactantes con infección congênita. Los RN se dividieron en dos grupos mayores, el último subdivido, de acuerdo a la oportunidad diagnóstica. Se describe la metodología diagnóstica, presentación clínica, tratamiento y el seguimiento posterior de los niños tratados. Se analizan las características de la experiencia y se discuten las condiciones específicas del diagnóstico, tratamiento y seguimiento de los niños estudiados. Se describen las recomendaciones empleadas en la provincia en el programa de control de Chagas perinatal así como las conclusiones derivadas de esta experiencia

Enfermedad de Chagas congénita en la ciudad de Salta, Argentina / Congenital Chagas disease in the city of Salta, Argentina

The immune response to Trypanosoma cruzi was studied in our hospital in 937 pregnant women(PW) and their 929 newborns(NB), group I; 4 NB from this center not included in the first group, group II and 35 NB derived from other centers, group III. Two positive results among indirect hemagglutination (IHA), complement fixation(CF) and indirect hemagglutination(IHA), complement fixation(CF) and indirect immunofluorescence(IIF) tests were considered as the criterion of previous infection with T. cruzi in PW. The presence of T. cruzi in blood, explored in fresh smears by serial micro-hematocrite and/or by xenodiagnosis, was the only criterion to define infection in NB. All NB were followed up by direct agglutination (DA) with or without 2 mercaptoethanol (DA-w2ME, DA-wo2ME) and IIF in order to establish the specific antibody kinetics. Clinical studies on NB with T. cruzi infection include routine laboratory tests. Benznidazole (3 to 7 mg/kg/day) and, in 1 case, nifurtimox (15 mg/kg/day) were employed as therapeutic agents. T. cruzi infection was confirmed in 149 PW(15.9), table I. These chagasic mothers delivered 6 chagasic NB (CCHD-NB), (4). Diagnosis of congenital Chagas' disease accounted for a total of 12 NB out of the 968 studied. 4 out of them were positive by both microhematocrite and blood smears and 7 by microhematocrite alone. Xenodiagnosis was performed in 2 NB resulting positive in both cases, table II. The most usual clinical findings included hepatomegaly (present in all cases), splenomegaly 8/12, jaundice 10/12 and prematurity 5/12, table 3. Laboratory findings showed anemia to be of hypochromic microcytic type in all cases.(ABSTRACT TRUNCATED AT 250 WORDS)