Experimental evaluation of a metofluthrin passive emanator against Aedes albopictus.

BACKGROUND: With the recent occurrence of locally transmitted Aedes-borne viruses in the continental United States and Europe, and a lack of effective vaccines, new approaches to control Aedes aegypti and Aedes albopictus are needed. In sub-tropical urban settings in the US, Ae. albopictus is a dominant nuisance and arbovirus vector species. Unfortunately, the vector control toolbox against Ae. albopictus is not as well developed as for Ae. aegypti. Here, we evaluate the efficacy, longevity, and range of protectiveness of a novel passive metofluthrin emanator (10% active ingredient in a polyethylene mesh) against Ae. albopictus indoors and outdoors. METHODS: Four studies were conducted comparing the presence of the metofluthrin emanator to a control lacking emanator with interest in quantifying efficacy by human landing counts. Studies evaluated the effect of an emanator at varying distances from one or more human volunteers indoors and outdoors. Efficacy of emanators over time since activation was also evaluated. RESULTS: Mixed-effects models determined that sitting in close proximity to an emanator reduced landings by 89.5% outdoors and by 74.6% indoors. The emanator was determined protective when located immediately next to a human volunteer outdoors but not uniformly protective when located further away. The emanator was protective at all tested distances from the device indoors. Mortality of mosquitoes exposed to metofluthrin emanators was ~2x higher than those who were not exposed in indoor conditions. Finally, a Generalized Additive Model determined that emanators used continuously outdoors lost their effect after 2.5 weeks and stopped inducing paralysis in mosquitoes after 3.8 weeks of use. CONCLUSIONS: We show strong and lasting efficacy of 10% metofluthrin emanators against field Ae. albopictus both in indoor and outdoor conditions. Metofluthrin emanators can protect people from Ae. albopictus bites, representing a viable option for reducing human-mosquito contacts at home and beyond.

Isolation of Heartland Virus from Lone Star Ticks, Georgia, USA, 2019.

Report of a human death and exposure of white-tailed deer to Heartland virus (HRTV) in Georgia, USA, prompted the sampling of questing ticks during 2018-2019 in 26 sites near where seropositive deer were captured and the residence of the human case-patient. We processed 9,294 Amblyomma americanum ticks in pools by virus isolation in Vero E6 cells and reverse transcription PCR. Positive pools underwent whole-genome sequencing. Three pools were positive for HRTV (minimum infection rate 0.46/1,000 ticks) and none for Bourbon virus. Cell cultures confirmed HRTV presence in 2 pools. Genome sequencing, achieved for the 3 HRTV isolates, showed high similarity among samples but marked differences with previously sequenced HRTV isolates. The isolation and genomic characterization of HRTV from A. americanum ticks in Georgia confirm virus presence in the state. Clinicians and public health professionals should be aware of this emerging tickborne pathogen.

The TIRS trial: protocol for a cluster randomized controlled trial assessing the efficacy of preventive targeted indoor residual spraying to reduce Aedes-borne viral illnesses in Merida, Mexico.

BACKGROUND: Current urban vector control strategies have failed to contain dengue epidemics and to prevent the global expansion of Aedes-borne viruses (ABVs: dengue, chikungunya, Zika). Part of the challenge in sustaining effective ABV control emerges from the paucity of evidence regarding the epidemiological impact of any Aedes control method. A strategy for which there is limited epidemiological evidence is targeted indoor residual spraying (TIRS). TIRS is a modification of classic malaria indoor residual spraying that accounts for Aedes aegypti resting behavior by applying residual insecticides on exposed lower sections of walls (< 1.5 m), under furniture, and on dark surfaces. METHODS/DESIGN: We are pursuing a two-arm, parallel, unblinded, cluster randomized controlled trial to quantify the overall efficacy of TIRS in reducing the burden of laboratory-confirmed ABV clinical disease (primary endpoint). The trial will be conducted in the city of Merida, Yucatan State, Mexico (population ~ 1million), where we will prospectively follow 4600 children aged 2-15 years at enrollment, distributed in 50 clusters of 5 × 5 city blocks each. Clusters will be randomly allocated (n = 25 per arm) using covariate-constrained randomization. A "fried egg" design will be followed, in which all blocks of the 5 × 5 cluster receive the intervention, but all sampling to evaluate the epidemiological and entomological endpoints will occur in the "yolk," the center 3 × 3 city blocks of each cluster. TIRS will be implemented as a preventive application (~ 1-2 months prior to the beginning of the ABV season). Active monitoring for symptomatic ABV illness will occur through weekly household visits and enhanced surveillance. Annual sero-surveys will be performed after each transmission season and entomological evaluations of Ae. aegypti indoor abundance and ABV infection rates monthly during the period of active surveillance. Epidemiological and entomological evaluation will continue for up to three transmission seasons. DISCUSSION: The findings from this study will provide robust epidemiological evidence of the efficacy of TIRS in reducing ABV illness and infection. If efficacious, TIRS could drive a paradigm shift in Aedes control by considering Ae. aegypti behavior to guide residual insecticide applications and changing deployment to preemptive control (rather than in response to symptomatic cases), two major enhancements to existing practice. TRIAL REGISTRATION: ClinicalTrials.gov NCT04343521 . Registered on 13 April 2020. The protocol also complies with the WHO International Clinical Trials Registry Platform (ICTRP) (Additional file 1). PRIMARY SPONSOR: National Institutes of Health, National Institute of Allergy and Infectious Diseases (NIH/NIAID).

Clinical and epidemiological comparison of Rickettsia parkeri rickettsiosis, related to Amblyomma triste and Amblyomma tigrinum, in Argentina.

The aim of this work was to compare the epidemiological and clinical characteristics of Rickettsia parkeri rickettsiosis related to Amblyomma triste and Amblyomma tigrinum ecological regions in Argentina. We reviewed cases of R. parkeri rickettsiosis from 2007 to 2017 evaluated at Muñiz Hospital, directly or through referral. Univariate analysis was used to examine the association between different variables and the disease related by each vector species. The eighteen cases of R. parkeri rickettsiosis included had fever, inoculation eschar and all except one had rash. Regional differences in epidemiological variables were identified, depending on the vector. There was a significantly increased risk of exposure to A. tigrinum in peri-domestic areas (odd ratio 12, p = 0.02), whereas an increased risk of exposure to A. triste was evident in wildlife areas (odd ratio 12, p = 0.02). Seasonality of R. parkeri rickettsiosis differed based on its vector. Cases associated with A. triste occurred predominantly during spring and summer, whereas those associated with A. tigrinum occurred during fall, winter, and springtime. Exanthema was maculopapular (13/18), maculo-vesicular (3/18) or petechial (1/18). No clinical differences were identified depending on the vector.

Zika Virus Infection in Pregnant Women, Yucatan, Mexico.

We report demographic, epidemiologic, and clinical findings for a prospective cohort of pregnant women during the initial phase of Zika virus introduction into Yucatan, Mexico. We monitored 115 pregnant women for signs of active or recent Zika virus infection. The estimated cumulative incidence of Zika virus infection was 0.31 and the ratio of symptomatic to asymptomatic cases was 1.7 (range 1.3-4.0 depending on age group). Exanthema was the most sensitive clinical sign but also the least specific. Conjunctival hyperemia, joint edema, and exanthema were the combination of signs that had the highest specificity but low sensitivity. We did not find evidence of vertical transmission or fetal anomalies, likely because of the low number of pregnant women tested. We also did not find evidence of congenital disease. Our findings emphasize the limited predictive value of clinical features in areas where Zika virus cocirculates with other flaviviruses.

Tenosinovitis por virus Chikungunya / Tenosynovitis due to Chikungunya virus

Se presenta a la consulta un hombre proveniente de la República Dominicana con una tenosinovitis del extensor del dedo medio derecho; en la convalecencia inmediata, segunda curva febril luego de 48 horas de permanecer asintomático de una enfermedad febril aguda, y marcada astenia, exantema pruriginoso, poliartralgias con impotencia funcional y rigidez articular generalizada. Los exámenes bioquímicos no aportaron datos de interés para el diagnóstico. La serología para virus dengue fue negativa. La detección de IgM y de anticuerpos neutralizantes para virus Chikungunya (CHIKV) fueron positivos.

We report the case of a man from Dominican Republic who consulted for a tenosynovitis of the right middle finger extensor; in the immediate convalescence second febrile curve, after 48 hours of no symptoms of an acute febrile illness, with marked fatigue, itchy rash, polyarthralgia, functional impairment and general stiffness. Biochemical tests did not provide useful data for diagnosis. Dengue virus serology was negative. Detection of IgM and neutralizing antibodies (PRNT) for Chikundunya virus (CHIKV) were positive.

Rickettsia parkeri rickettsiosis in different ecological regions of Argentina and its association with Amblyomma tigrinum as a potential vector.

Rickettsia parkeri, a newly recognized tick-borne pathogen of humans in the Americas, is a confirmed cause of spotted fever group rickettsiosis in Argentina. Until recently, almost all cases of R. parkeri rickettsiosis in Argentina have originated from the Paraná River Delta, where entomological surveys have identified populations of R. parkeri-infected Amblyomma triste ticks. In this report, we describe confirmed cases of R. parkeri rickettsiosis from Córdoba and La Rioja provinces, which are located several hundred kilometers inland, and in a more arid ecological region, where A. triste ticks do not occur. Additionally, we identified questing A. tigrinum ticks naturally infected with R. parkeri in Córdoba province. These data provide evidence that another human-biting tick species serves as a potential vector of R. parkeri in Argentina and possibly, other countries of South America.

[Tenosynovitis due to Chikungunya virus]. / Tenosinovitis por virus Chikungunya.

We report the case of a man from Dominican Republic who consulted for a tenosynovitis of the right middle finger extensor; in the immediate convalescence second febrile curve, after 48 hours of no symptoms of an acute febrile illness, with marked fatigue, itchy rash, polyarthralgia, functional impairment and general stiffness. Biochemical tests did not provide useful data for diagnosis. Dengue virus serology was negative. Detection of IgM and neutralizing antibodies (PRNT) for Chikundunya virus (CHIKV) were positive.

Tenosinovitis por virus Chikungunya. / [Tenosynovitis due to Chikungunya virus].

We report the case of a man from Dominican Republic who consulted for a tenosynovitis of the right middle finger extensor; in the immediate convalescence second febrile curve, after 48 hours of no symptoms of an acute febrile illness, with marked fatigue, itchy rash, polyarthralgia, functional impairment and general stiffness. Biochemical tests did not provide useful data for diagnosis. Dengue virus serology was negative. Detection of IgM and neutralizing antibodies (PRNT) for Chikundunya virus (CHIKV) were positive.

[Outbreak of St. Louis encephalitis in the Metropolitan Buenos Aires Area]. / Brote de encefalitis de San Luis en el área metropolitana Buenos Aires.

We describe the epidemiological and clinical findings of 13 patients with diagnosis of infection by St. Louis encephalitis virus, transmitted between January and March 2010 in Buenos Aires Metropolitan Area (AMBA). Thirteen patients, average age 38 years, had an acute onset with hyperthermia and headache. Between days two and ten of the onset of symptoms, 7/13 patients had signs and symptoms of neurological involvement. This was characterized by meningitis without encephalic sings in 1/7 and in 6/7 the most frequent findings were: stiff neck, disorientation, photophobia, confusion and language impairment. Two MR and one EEG revealed signs of involvement of temporal lobes. The cerebrospinal fluid showed pleocytosis with predominance of mononuclear cells, normal glucose and moderately elevated protein. There were no fatalities cases. In 6/13 patients the initial clinical suspicion was dengue. As epidemic virus circulation had not been previously reported in the AMBA it can be considered an outbreak of St. Louis encephalitis for the spatial and temporal clustering of cases.

Rickettsia parkeri Rickettsiosis, Argentina.

Rickettsia parkeri, a recently identified cause of spotted fever rickettsiosis in the United States, has been found in Amblyomma triste ticks in several countries of South America, including Argentina, where it is believed to cause disease in humans. We describe the clinical and epidemiologic characteristics of 2 patients in Argentina with confirmed R. parkeri infection and 7 additional patients with suspected R. parkeri rickettsiosis identified at 1 hospital during 2004-2009. The frequency and character of clinical signs and symptoms among these 9 patients closely resembled those described for patients in the United States (presence of an inoculation eschar, maculopapular rash often associated with pustules or vesicles, infrequent gastrointestinal manifestations, and relatively benign clinical course). Many R. parkeri infections in South America are likely to be misdiagnosed as other infectious diseases, including Rocky Mountain spotted fever, dengue, or leptospirosis.

Brote de encefalitis de San Luis en el Área Metropolitana Buenos Aires / Outbreack of St. Luis encephalitis in the Metropolitan Buenos Aires Area

Se describen los hallazgos epidemiológicos y clínicos de 13 enfermos con diagnóstico de infección por virus de la encefalitis de San Luis, con transmisión entre enero y marzo de 2010, en el Area Metropolitana Buenos Aires (AMBA). Los 13 enfermos, promedio de edad 38 años, tuvieron un comienzo agudo caracterizado por hipertermia y cefalea. Entre los días dos y diez de iniciados los síntomas, 7/13 enfermos tuvieron signos y síntomas de compromiso neurológico caracterizado por meningitis sin signos encefálicos en 1/7. En 6/7 los hallazgos más frecuentes fueron: rigidez de nuca, desorientación temporoespacial, fotofobia, confusión y alteración del lenguaje. Dos resonancias magnéticas y un electroencefalograma presentaron signos de afectación de lóbulos temporales. El líquido cefalorraquídeo se caracterizó por pleocitosis con predominio de células mononucleadas, glucorraquia normal y discreto aumento de proteínas. No hubo casos fatales. En 6/13 pacientes la sospecha clínica inicial fue dengue. Por la agrupación espacial y temporal de los casos puede considerarse un brote epidémico, el primero conocido en el AMBA, ya que no se había notificado previamente la circulación epidémica del virus.

We describe the epidemiological and clinical findings of 13 patients with diagnosis of infection by St. Louis encephalitis virus, transmitted between January and March 2010 in Buenos Aires Metropolitan Area (AMBA). Thirteen patients, average age 38 years, had an acute onset with hyperthermia and headache. Between days two and ten of the onset of symptoms, 7/13 patients had signs and symptoms of neurological involvement. This was characterized by meningitis without encephalic sings in 1/7 and in 6/7 the most frequent findings were: stiff neck, disorientation, photophobia, confusion and language impairment. Two MR and one EEG revealed signs of involvement of temporal lobes. The cerebrospinal fluid showed pleocytosis with predominance of mononuclear cells, normal glucose and moderately elevated protein. There were no fatalities cases. In 6/13 patients the initial clinical suspicion was dengue. As epidemic virus circulation had not been previously reported in the AMBA it can be considered an outbreak of St. Luis encephalitis for the spatial and temporal clustering of cases.

[Community acquired pneumonia and pulmonary hemorrhage in leptospirosis in the Buenos Aires metropolitan area]. / Neumonía aguda de la comunidad y hemorragia pulmonar por leptospirosis en el área metropolitana Buenos Aires.

The aim of this paper is to report the epidemiological, clinical and diagnosis findings of pneumonia and pulmonary hemorrhage observed in patients with leptospirosis in the period January 2007 to October 2009. A 64% (20/31) of patients diagnosed with leptospirosis presented pneumonia. Fifteen of them (75%) had severe pneumonia, of which seven (35%) were pulmonary hemorrhage. In ten patients (32%) reason for consultation and clinical early stage was a secretory gastroenteritis with fever and abdominal pain. Jaundice was only expressed in eleven patients (35%). The technique of chain reaction (PCR) was useful for diagnosis in samples obtained post mortem. A strain classified in serogroup canicola was isolated from blood culture. Pneumonia was classified into three types: non-severe pneumonia course with little overall impact; severe pneumonia associated with systemic clinical forms with jaundice, renal failure, thrombocytopenia, and pulmonary hemorrhage, and of serious course, not associated with jaundice, kidney failure or thrombocytopenia. Antibiotic treatment started in the early stages of disease (average 3.2 days) had no influence on the development of severe pneumonia. It is puggested to consider three clinical forms of leptospirosis: anicteric, icteric (with its evolutionary variants) and pulmonary hemorrhage.

Neumonía aguda de la comunidad y hemorragia pulmonar por leptospirosis en el área metropolitana Buenos Aires / Community acquired pneumonia and pulmonary hemorrhage in leptospirosis in the Buenos Aires metropolitan area

El objetivo del trabajo es comunicar los hallazgos epidemiológicos, clínicos y de diagnóstico de la neumonía y hemorragia pulmonar por leptospirosis, en el período enero 2007 a octubre 2009. Un 64% (20/31) de pacientes con diagnóstico de leptospirosis tuvieron neumonía. Quince de ellos (75%) presentaron neumonía grave, de los cuales siete (35%) desarrollaron hemorragia pulmonar. En diez enfermos (32%) el motivo de consulta e inicio del cuadro clínico fue una gastroenteritis secretoria con fiebre y dolor abdominal. La ictericia sólo se manifestó en once pacientes (35%). La técnica de reacción en cadena de la polimerasa (PCR) fue útil para el diagnóstico en muestra obtenida post mortem. De un hemocultivo se aisló una cepa clasificada dentro del serogrupo canicola. Se clasificaron las neumonías en tres tipos: neumonías de curso no grave con escasa repercusión general; neumonías graves asociadas a formas clínicas sistémicas con ictericia, insuficiencia renal, trombocitopenia y hemorragia pulmonar; también de curso grave, no asociada a ictericia, insuficiencia renal o trombocitopenia grave. El tratamiento antibiótico iniciado en los primeros días de enfermedad (promedio 3.2 días) no tuvo influencia en la evolución de las neumonías graves. Se plantea además considerar tres formas clínicas de leptospirosis: anictérica, ictérica (con sus variantes evolutivas) y hemorragia pulmonar.

The aim of this paper is to report the epidemiological, clinical and diagnosis findings of pneumonia and pulmonary hemorrhage observed in patients with leptospirosis in the period January 2007 to October 2009. A 64% (20/31) of patients diagnosed with leptospirosis presented pneumonia. Fifteen of them (75%) had severe pneumonia, of which seven (35%) were pulmonary hemorrhage. In ten patients (32%) reason for consultation and clinical early stage was a secretory gastroenteritis with fever and abdominal pain. Jaundice was only expressed in eleven patients (35%). The technique of chain reaction (PCR) was useful for diagnosis in samples obtained post mortem. A strain classified in serogroup canicola was isolated from blood culture. Pneumonia was classified into three types: non-severe pneumonia course with little overall impact; severe pneumonia associated with systemic clinical forms with jaundice, renal failure, thrombocytopenia, and pulmonary hemorrhage, and of serious course, not associated with jaundice, kidney failure or thrombocytopenia. Antibiotic treatment started in the early stages of disease (average 3.2 days) had no influence on the development of severe pneumonia. It is puggested to consider three clinical forms of leptospirosis: anicteric, icteric (with its evolutionary variants) and pulmonary hemorrhage.

Brote de dengue autóctono en el área metropolitana Buenos Aires: Experiencia del Hospital de Enfermedades Infecciosas F. J. Muñiz / Outbreak of indigenous dengue in the Buenos Aires Metropolitan Area: Experience of the F.J. Muñiz Hospital

Como consecuencia de la epidemia de dengue que afectó a la República de Bolivia y provincias del norte argentino, se produjo por primera vez un brote de dengue autóctono en el Area Metropolitana Buenos Aires. A partir de enero de 2009 asistimos casos de dengue importado hasta la tercera semana de marzo, cuando aparecieron los primeros casos por transmisión local, tendencia que se mantuvo hasta mediados de mayo. La mayor concentración de casos autóctonos atendidos residía en la región oeste de la ciudad de Buenos Aires y en localidades de los partidos de 3 de Febrero y La Matanza, que limitan con ella. Existieron factores concurrentes para que se produjera este brote: alta densidad vectorial, viajeros provenientes de regiones epidémicas concentrados por su domicilio en las áreas donde luego se produjo la transmisión local. El 95% ingresaron en los primeros días de viremia y en un período climático caracterizado por temperaturas medias elevadas que se mantuvieron hasta mediados de otoño. De los nueve pacientes con signos de alarma para el desarrollo de dengue grave, siete fueron casos autóctonos que no tenían antecedentes de haber padecido previamente dengue. Se comunican los hallazgos clínicos y epidemiológicos y se analizan los factores que regularon la transmisión.

As a consequence of the dengue epidemic in the Bolivian Republic and the northern provinces of Argentina, an outbreak of indigenous dengue occurred for the first time in the Buenos Aires Metropolitan Area. Since January 2009 we assisted imported dengue cases coming from epidemic regions; later, around the end of March, and until middle autumn, indigenous cases appeared. The major concentration of these indigenous cases was in the west area of Buenos Aires City and in the neighboring localities 3 de Febrero and La Matanza. There were several factors that made the local transmission possible: a high vector density, people traveling from epidemic areas and clustering in the geographical zone where the indigenous epidemic occurred, during a period with high medium temperatures, entering 95% of the imported cases during the first days of the viremia. Of the nine patients with alarming signs for the development of severe dengue, seven were indigenous cases with no previous history of dengue infections. We report the clinical and epidemiological findings, and we analyze the factors which regulated the transmission.

Análisis clínico y epidemiológico de mordeduras de rata en Buenos Aires / Clinical and epidemiological analysis of rat bite in Buenos Aires

Analizamos 62 casos de mordedura de rata asistidos entre los años 2002 y 2008. cuarenta de ellos ocurrieron en la ciudad de Buenos Aires, sin clara relación con las condiciones urbanas o socioeconómicas de los afectados. Las mordeduras producidas durante el día ocurrieron por invasión del hombre al hábitat de los roedores, situación inversa a las sucedidas durante la noche. En el 79% de los casos fueron afectados los miembros y en un 16% la cara. Cinco pacientes desarrollaron manifestaciones clínicas de enfermedad por mordedura de rata. Se discute el valor de la profilaxis post exposición con antibióticos.

We report 62 cases of rat bites that occurred between 2002 and 2008. Forty of these happened in Buenos Aires city, unrelated to social class or urban conditions. The bites occurring in daylight were related to invasion of the animal habitat by man, and to rat activity during the night. In 79% of the cases the rat bite was in the limbs and in 16% in the face. Five patients developed clinical manifestations of rat bite fever. We discuss the value of post exposition prophylaxis with antibiotics.

[Outbreak of indigenous dengue in the Buenos Aires Metropolitan Area. Experience of the F. J. Muñiz Hospital]. / Brote de dengue autóctono en el área metropolitana de Buenos Aires. Experiencia del Hospital de Enfermedades Infecciosas F. J. Muñiz.

As a consequence of the dengue epidemic in the Bolivian Republic and the northern provinces of Argentina, an outbreak of indigenous dengue occurred for the first time in the Buenos Aires Metropolitan Area. Since January 2009 we assisted imported dengue cases coming from epidemic regions; later, around the end of March, and until middle autumn, indigenous cases appeared. The major concentration of these indigenous cases was in the west area of Buenos Aires City and in the neighboring localities 3 de Febrero and La Matanza. There were several factors that made the local transmission possible: a high vector density, people traveling from epidemic areas and clustering in the geographical zone where the indigenous epidemic occurred, during a period with high medium temperatures, entering 95% of the imported cases during the first days of the viremia. Of the nine patients with alarming signs for the development of severe dengue, seven were indigenous cases with no previous history of dengue infections. We report the clinical and epidemiological findings, and we analyze the factors which regulated the transmission.

Epidemiological and molecular evidence of two events of father-to-child HIV type 1 horizontal transmission.

HIV-1 infection in children less than 15 years of age is mainly due to mother-to-child transmission. The aim of this work was to investigate molecular evidence to prove father-to-be horizontal transmission in two possible events of transmission. In the first event a boy was identified as HIV infected at 2-3 years of age. At the same time infection was confirmed in the father, while mother and siblings were negative. In the second event a girl was negative for HIV at age 1 and identified as HIV-1 infected at age 6. The father's HIV infection was diagnosed in the same period while the mother was repeatedly negative. No evidence of sexual assault or transfusion was recorded in any case. Peripheral blood mononuclear cells were obtained from both fathers and children. After PCR amplification, the C2V3 region of the envelope gene and the region coding for amino acid 132 of p24 up to amino acid 40 of p7 of the gag gene were sequenced. Genetic distance measurements and phylogenetic tree analysis showed that in both cases the father's and child's viral sequences were closely related. They were distinct when compared to Argentina sequences including sequences from the same geographic region. Epidemiological and molecular data strongly suggest that horizontal transmission had occurred, probably related to the close father-to-child contact.