Analysis of the tick communities associated to domestic mammals in rural areas of the Yungas montane forest from Argentina.

The aim of this work was to describe the tick community associated to domestic mammals in rural areas from the Yungas lower montane forest of Argentina. The circulation of tick-borne pathogens was also analyzed. Samples of ticks parasitizing cattle, horses, sheep and dogs were carried out in different seasons, and questing ticks were collected from vegetation and analyzed to detect the presence of Rickettsia, Ehrlichia, Borrelia and Babesia by a battery of different PCRs. The structure of the tick communities was analyzed through the Chao1 species richness estimator, the Shannon-Wiener index and the Horn index of community similarity. Eight tick species were collected in the study area: Amblyomma sculptum, Rhipicephalus microplus, Amblyomma hadanii, Dermacentor nitens, Amblyomma ovale, Haemaphysalis juxtakochi, Ixodes pararicinus and Rhipicephalus sanguineus sensu stricto. However, A. sculptum was by far the dominant species in the tick assemblages analyzed, and this was reflected in the low diversity values obtained. Dermacentor nitens, A. sculptum and R. microplus were the three species associated to horses. The predominance of A. sculptum was also observed in the tick samples obtained from dogs, even on two tick species, namely A. ovale and R. sanguineus s.s., which have dogs as the principal domestic host. Rhipicephalus microplus and A. sculptum were the most abundant ticks on cattle, while few specimens of I. pararicinus, A. hadanii and D. nitens were found on bovines. Dermacentor nitens ticks were found to be infected with B. caballi, which indicate the circulation of this pathogen of horses in the Yungas area. The detection of a strain of Borrelia sp. belonging to the B. burgdorferi s.l. complex in I. pararicinus is consistent with previous findings made in Argentina, but the public health relevance of this vector-microorganism association is far from being similar to that occurs in the northern hemisphere because there are practically no records of these tick species parasitizing humans in South America. The tick community of rural areas of the Yungas lower montane forest is composed by species which are potential vectors of pathogenic microorganism with veterinary and public health importance, circulating in a human-wildlife-livestock interface.

Ticks (Acari: Ixodidae, Argasidae) associated with wild birds in Argentina.

The aim of this study was to report tick infestations on wild birds from four Phytogeographic Provinces of Argentina. A total of 1085 birds was captured (124 species, 97 genera, 29 families and 13 orders), and ticks were collected from 265 birds (48 species, 40 genera and five orders). A total of 1469 ticks (1102 larvae, 363 nymphs and 4 females) belonging to 15 tick species (Amblyomma calcaratum, Amblyomma dubitatum, Amblyomma nodosum, Amblyomma ovale, Amblyomma parvum, Amblyomma sculptum, Amblyomma tigrinum, Amblyomma triste, Haemaphysalis juxtakochi, Haemaphysalis leporispalustris, Ixodes auritulus sensu lato, Ixodes pararicinus, Ixodes silvanus, Ixodes sp. cf. I. affinis and Ornithodoros sp. cf. O. mimon). Eighty-one new associations between bird species and stages of tick species are detected. The families Thamnophilidae, Turdidae, Thraupidae, Passerellidae, Furnariidae and Troglodytidae were the most prevalent. According to the Phytogeographic Provinces involved in this study, the prevalence of infection for each of them in birds was: (1) Chaco: 28.2% (11 tick species); (2) Yungas: 22.0% (8 tick species); (3) Espinal: 11.1% (2 tick species); and (4) Pampa: 3.9% (1 tick species). This study provided information on the diversity of tick species that parasitize wild birds, the variability of the specific tick-bird associations between the different Phytogeographic Provinces and the relevance of some families of birds as hosts of different tick species.

Use of Aedes aegypti Oviposition Surveillance and a Geographic Information System for Planning Anti-Vectorial Measures.

Arboviruses transmitted by Aedes aegypti pose a threat to global public health. Because there are no vaccines or drugs available, the prevention of these diseases in Argentina is based on integrated vector control. In this work, the spatiotemporal dynamics of the vector distribution was analyzed by monitoring oviposition. This information allowed the planning of anti-vector interventions and the evaluation of their effect on the relative abundance of mosquito populations in San Ramón de la Nueva Orán. Observed data were compared with the eggs expected via a statistical model based on meteorological variables. The oviposition substrate preference of mosquito females was also evaluated, and the possible relationship between the relative abundance of the vector and sociodemographic and environmental variables (normalized difference vegetation index and normalized difference water index) was explored. A total of 4,193 eggs of Ae. aegypti were collected, and spatial clusters were detected for all months for which the presence of the mosquito was reported. The observed number of eggs was significantly less than the expected-corrected egg abundance. A significant correlation of oviposition activity was found with three sociodemographic variables, whereas no significant correlation was found with mean or median values of the environmental variables studied. This monitoring strategy made it possible to address the interventions and evaluate them, proposing them as good complementary tools for the control of Ae. aegypti in northern Argentina.

Leishmaniasis tegumentaria y flebótomos en la localidad de Colonia Santa Rosa del norte de Argentina / Tegumentary leishmaniasis and sandflies in Colonia Santa Rosa locality in northern Argentina

Resumen La leishmaniasis tegumentaria (LT) es causada por parásitos del género Leishmania y transmitida por especies de flebótomos, insectos pertenecientes al orden Diptera, familia Psychodidae. El objetivo de este trabajo fue analizar la presencia de casos de LT y su variación temporal entre 1985 y 2019, las formas clínicas, la ubicación de las lesiones en los pacientes y la presencia de flebótomos en la localidad de Colonia Santa Rosa, del norte de Argentina. Los pacientes se diagnosticaron mediante frotis e intradermorreacción de Montenegro. Se colocaron trampas CDC en 14 sitios en el horario de 19 a 7. Se diagnosticaron 120 casos de LT y la prevalencia global fue del 0,75% (^16.000 habitantes). Los pacientes presentaron formas cutáneas simples y múltiples (88,79%) y mucocutáneas (10,83%). Las lesiones cutáneas fueron más frecuentes en extremidades inferiores. Del total de flebótomos, Nyssomyia neivai fue la especie predominante (95%), y, en menor proporción, estuvieron presentes Migonemyia migonei (1,9%), complejo cortelezzii (1,3%) y Evandromyia sallesi (0,09%). La persistente ocurrencia de casos y la presencia de flebótomos en la citada localidad nos sugiere la transmisión endémica en la zona. Esto senala la necesidad de planificar medidas preventivas y de control de la LT en el norte de Argentina.

Abstract Tegumentary leishmaniasis (TL) is caused by parasites of the genus Leishmania and transmitted by the sandfly species, insects belonging to the order Diptera, family Psychodidae. Historically, the most endemic area of TL in Argentina has been the northern region. The aim of this work was to analyze the presence and temporal variation of TL cases reported between 1985 and 2019 in Colonia Santa Rosa locality, northern Argentina. Furthermore, its clinical forms were characterized and sandflies were captured. Patients were diagnosed by smear and the Montenegro skin test. For sampling, CDC light traps were placed at 14 sites from 7pm to 7am. The correlation between vegetation cover and sandfly abundance was also studied. One hundred and twenty TL cases were diagnosed and the overall prevalence was 0.75% (M6 000 inhabitants). Patients presented simple and multiple cutaneous leishmaniasis (88.79%) and the mucocutaneous form (10.83%). Skin lesions were more frequent on the lower extremities (46.73%). Of the total number of sandflies, Nyssomyia neivai (95%) was the predominant species followed by Migonemyia migonei (1.9%), cortelezzii complex (1.3%) and Evandromyia sallesi (0.09%). The persistent occurrence of cases and the presence of sandflies in the locality suggest the existence of endemic transmission in the area. This highlights the need to design prevention and control measures for TL in northern Argentina.

[Tegumentary leishmaniasis and sandflies in Colonia Santa Rosa locality in northern Argentina]. / Leishmaniasis tegumentaria y flebótomos en la localidad de Colonia Santa Rosa del norte de Argentina.

Tegumentary leishmaniasis (TL) is caused by parasites of the genus Leishmania and transmitted by the sandfly species, insects belonging to the order Diptera, family Psychodidae. Historically, the most endemic area of TL in Argentina has been the northern region. The aim of this work was to analyze the presence and temporal variation of TL cases reported between 1985 and 2019 in Colonia Santa Rosa locality, northern Argentina. Furthermore, its clinical forms were characterized and sandflies were captured. Patients were diagnosed by smear and the Montenegro skin test. For sampling, CDC light traps were placed at 14 sites from 7pm to 7am. The correlation between vegetation cover and sandfly abundance was also studied. One hundred and twenty TL cases were diagnosed and the overall prevalence was 0.75% (≈16 000 inhabitants). Patients presented simple and multiple cutaneous leishmaniasis (88.79%) and the mucocutaneous form (10.83%). Skin lesions were more frequent on the lower extremities (46.73%). Of the total number of sandflies, Nyssomyia neivai (95%) was the predominant species followed by Migonemyia migonei (1.9%), cortelezzii complex (1.3%) and Evandromyia sallesi (0.09%). The persistent occurrence of cases and the presence of sandflies in the locality suggest the existence of endemic transmission in the area. This highlights the need to design prevention and control measures for TL in northern Argentina.

Tegumentary leishmaniasis and sand flies in a border area between Argentina and Bolivia.

Background: Some sand flies are of medical importance because they are vectors of Leishmania parasites that are responsible for leishmaniasis. The aim of this study was to make a retrospective epidemiological analysis of tegumentary leishmaniasis (TL), to identify Leishmania spp. from patient isolates and to describe the diversity of sand flies from a border area between Bolivia and Argentina. Methods: TL cases included in the study were diagnosed in an endemic area of the north of Argentina from 1985 to 2017. The parasites isolated were characterized by the cytochrome B method. Sand flies were captured with Centers for Disease Control traps in Aguas Blancas and Media Luna-Algarrobito localities. Results: A total of 118 cases of TL were analysed. Eight isolates were characterized as Leishmania (Viannia) braziliensis. A total of 1291 sand flies were captured, including Nyssomyia neivai, Cortelezzii complex, Evandromyia sallesi, Migonemyia migonei and Micropygomyia quinquefer. Within the area, sand flies were found in the backyards of houses. Conclusions: In this region there exists the possibility of peridomestic transmission of TL in the neighbourhoods peripheral to the urban area and in rural environments as well as the risk of transmission to travellers that pass through the customs offices.

Vegetation Cover and Microspatial Distribution of Sand Flies (Diptera: Psychodidae) in an Endemic Locality for Cutaneous Leishmaniasis in Northern Argentina.

The sand fly fauna in Hipólito Yrigoyen, Argentina, a locality where cutaneous leishmaniasis cases occur, was surveyed with zones of higher abundance of sand flies correlated to vegetation cover estimated through normalized difference vegetation index (NDVI). Sand flies were collected with 10 CDC traps during six nights, from December 2009 to January 2010. A map was built of expected sand flies abundance in which levels of NDVI were categorized. In total, 1,392 Phlebotominae (Diptera: Psychodidae) specimens were collected, comprised of the following species: Nyssomyia neivai (Pinto 1926), Migonemyia migonei (França 1920), species of the cortelezzii complex (Brèthes 1923), Evandromyia sallesi (Galvão & Coutinho 1940), and Psathyromyia shannoni (Dyar 1929). Positive correlations were found between the abundance of sand flies and the NDVI (P < 0.05) for buffer areas of <150 m radii from the trap location points, i.e., the sand fly abundance was greater where vegetation cover and density were greater. In this context, plant cover should be taken into account to prioritize surveillance and control areas within the program of sand flies control in northern Argentina.