Onilda Santos da Silva

Ocorrência de protozoários e helmintos em amostras de fezes de cães errantes da Cidade de Itapema, Santa Catarina

Samples of feces from dogs seized by the health surveillance program of Itapema city, SC, were studied. From 158 samples examined 121 (76.6%) were positive, with a prevalence of Ancylostoma spp (70.9%), followed by Toxocara canis (14.5%), Trichuris vulpis (13.9%), Isospora spp (6.3%) and Dipylidium caninum (1.9%).

AEDES AEGYPTI AND AEDES ALBOPICTUS (DIPTERA: CULICIDAE): COEXISTENCE AND SUSCEPTIBILITY TO TEMEPHOS, IN MUNICIPALITIES WITH OCCURRENCE OF DENGUE AND DIFFERENTIATED CHARACTERISTICS OF URBANIZATION

INTRODUCTION The aim of the present study was to verify the coexistence between Aedes aegypti and Aedes albopictus populations in municipalities of the States of Paraná and Santa Catarina with different urbanization profiles where dengue occurs and evaluate their susceptibility to the organophosphate temephos. METHODS The number of eggs per ovitrap were counted and incubated for hatching to identify the species. Data analysis of the populations was conducted to determine randomness and aggregation, using the variance-to-mean ratio (index of dispersion). Susceptibility to temephos was evaluated by estimation of the resistance ratios RR50 and RR95. Aedes aegypti samples were compared with the population Rockefeller and Aedes albopictus samples were compared with a population from the State of Santa Catarina and with the Rockefeller population. RESULTS Coexistence between Aedes aegypti and Aedes albopictus and the aggregation of their eggs were observed at all the sites analyzed in the State of Paraná. CONCLUSIONS All the Aedes aegypti populations from the State of Parana showed alteration in susceptibility status to the organophosphate temephos, revealing incipient resistance. Similarly, all the Aedes albopictus populations (States of Paraná and Santa Catarina) presented survival when exposed to the organophosphate temephos.

First report on susceptibility of wild Aedes aegypti (Diptera: Culicidae) using Carapa guianensis (Meliaceae) and Copaifera sp. (Leguminosae)

Oils of Carapa guianensis and Copaifera spp. are well known in the Amazonian region as natural insect repellent, and studies have reported their efficiency as larvicide against some laboratory mosquito species. However, in wild populations of mosquitoes, these oils have not yet been evaluated. Thus, the objective of this study was to investigate their efficiency as larvicide in wild populations of Aedes aegypti with a history of exposure to organophosphate. The susceptibility of larvae was determined under three different temperatures, 15°C, 20°C, and 30°C. For each test, 1,000 larvae were used (late third instar and early fourth instar—four replicates of 25 larvae per concentration). Statistical tests were used to identify significant differences. The results demonstrated that as the laboratory A. aegypti, the wild populations of A. aegypti were also susceptible to C. guianensis and Copaifera sp. oils. The lethal concentrations for Copaifera sp. ranged from LC50 47 to LC90 91 (milligrams per liter), and for C. guianensis, they were LC50 136 to LC90 551 (milligrams per liter). In relation to different temperature, the effectiveness of the oils on larvae mortality was directly related to the increase of temperature, and better results were observed for temperature at 25°C. The results presented here indicate the potential larvicidal activity of C. guianensis and species of Copaifera, in populations of A. aegypti from the wild. Therefore, the results presented here are very important since such populations are primarily responsible for transmitting the dengue virus in the environment.

Ocorrência de cães errantes soropositivos para Leptospira spp. na Cidade de Itapema, Santa Catarina, Brasil

This study aimed to verify Leptospira spp. serovar infections in stray dogs in Itapema, Santa Catarina, Brazil. Serum samples were collected from 590 stray dogs and tested against 25 Leptospira spp. serovars using the microscopic agglutination test. Prevalence of anti-leptospiral antibodies against one or more serovars was 10.5%. The most frequent serovar was pyrogenes, positive in 26 (18.0%) samples, followed by canicola with 20 (13.8%) and icterohaemorragiae and copenhageni with 18 (12.5%, with antibody titers from 1:100 to 1:3,200). Significant prevalence (10.4 to 11.1%) was also detected against serovars castellonis, butembo, and grippothyphosa.

Larvicidal effect of dried leaf extracts from Pinus caribaea against Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae)

In this study, the larvicidal activity of dried leaf extracts from Pinus caribaea Morelet against Aedes aegypti was evaluated for the first time. Pinus caribaea extracts were obtained by macerating dried leaves in alkaline hydroethanol, ethanol and acetone solutions followed by evaporation under reduced pressure. The lignin content was quantified using the thioglycolic acid complexation method. Lethality bioassays (LC(50) and LC(90)) were carried out in accordance with the recommendations of the World Health Organization. The results showed that the acetone extract from Pinus caribaea was more active, and that larvicidal activity was associated with lignin concentration.

Susceptibility of Aedes aegypti (Diptera: Culicidae) to Acanthamoeba polyphaga (Sarcomastigophora: Acanthamoebidae)

To date there is no report on mosquitoes infected with free-living amoebae. For this reason, the aim of this study was to verify if Aedes aegypti could be susceptible to Acanthamoeba polyphaga under laboratory conditions, so trophozoites were offered as a unique food resource for larvae of first instar. The results show that those amoebae are able to infect and colonize the mosquito gut and could be re-isolated of all stages of the mosquito (larvae, pupae, and adults).

Catalogue of the mite family Tydeidae (Acari: Prostigmata) with the world key to the species.

Members of the Tydeidae are cosmopolitan, soft-bodied, striated or reticulated mites that are reported to be mainly phytophages, mycophages, pollenophages, insect parasites or scavengers. This catalogue includes 328 species belonging to 30 genera, and their distributions and type habitat. Until now, Brachytydeus comprises the largest number of species with 200, followed by Tydeus, with 50 species, and Pretydeus and Pseudolorryia, with 12 species each. An updated list of the Tydeidae (Acari: Prostigmata), a world key to the species and data on the zoogeographical distribution of the species are presented.

Larvicidal and residual activity of imidazolium salts against Aedes aegypti (Diptera: Culicidae): Imidazolium salts against Aedes aegypti

BACKGROUND Aedes aegypti is an important mosquito species that can transmit several arboviruses such as dengue fever, yellow fever, chikungunya and zika. Because these mosquitoes are becoming resistant to most chemical insecticides used around the world, studies with new larvicides should be prioritized. Based on the known biological profile of imidazolium salts (IS), the objective of this study was to evaluate the potential of six IS as larvicides against Ae. aegypti, as tested against Ae. aegypti larvae. Larval mortality was measured after 24 and 48 h, and residual larvicidal activity was also evaluated. RESULTS Promising results were obtained with aqueous solutions of two IS: 1-n-octadecyl-3-methylimidazolium chloride (C18 MImCl) and 1-n-hexadecyl-3-methylimidazolium methanesulfonate (C16 MImMeS), showing up to 90% larval mortality after 48 h exposure. C18 MImCl was more effective than C16 mIMeS, causing mortality until day 15 after exposure. An application of C18 MImCl left to dry under ambient conditions for at least 2 months and then dissolved in water showed a more pronounced residual effect (36 days with 95% mortality and 80% mortality up to 78 days). CONCLUSION This is the first study to show the potential of IS in the control of Ae. aegypti. Further studies are needed to understand the mode of action of these compounds in the biological development of this mosquito species.

Histological and Histochemical Characterization of the Midgut of Healthy Aedes aegypti Larvae

Aedes aegypti (Diptera, Culicidae) is the predominant mosquito vector of several arboviruses such as dengue fever, yellow fever, chikungunya and zika. The larval stage is the major period of feeding and growth of these insects. Many of the products tested for Ae. aegypti control are ingested by the larvae in their natural environment or under laboratory conditions. In some situations, the identification of tissue lesions caused by the ingestion of such products serves as the primary way to understand their mechanism of action and confirm their effectiveness. Original Research Article Lemos et al.; ARRB, 22(1): 1-15, 2018; Article no.ARRB.37443 2 Therefore, we aimed to conduct studies on the histological and histochemical characteristics of Ae. aegypti larvae in order to contribute to a better understanding of the pathogenicity caused by chemical or biological products for larval control. Therefore, we characterized tissues in the midgut of healthy Ae. aegypti larvae and present high quality images. These images are intended for comparison with results of morphohistochemical studies testing the effect of control substances in mosquito larvae.

Comparison of biological development of Blattisocius dentriticus (Blattisocidae) fed on Tyrophagus putrescentiae (Acaridae) and Megninia ginglymura (Analgidae)

ABSTRACT This study evaluated Blattisocius dentriticus (Berlese) as a candidate predator of two mite species of public-health importance for humans and animals. We observed the development time, reproduction, survival and sex ratio of this predatory mite when fed on one of two pest mites, Tyrophagus putrescentiae (Schrank) and Megninia ginglymura (Mégnin), under laboratory conditions, at a temperature of 25 ± 1°C and 80 ± 5% relative humidity, in the dark. The study started with 30 experimental units containing M. ginglymura as a food source and 30 containing T. putrescentiae, each with an egg of B. dentriticus obtained from fertilized females. The length of the pre-oviposition period was significantly longer when M. ginglymura was used as food, compared to T. putrescentiae. The life-table parameters for B. dentriticus differed on the two diets. These parameters indicated that the population of B. dentriticus fed on T. putrescentiae increased about 7.53 times (Ro = 7.53) every 14.3 days (T = 14.3), corresponding to a daily population growth of about 15% (λ = 1.15), i.e. a production of 0.14 female per female per day (rm = 0.14). B. dentriticus fed on M. ginglymura showed lower values (Ro = 2.79; T = 23.76; λ = 1.04; rm = 0.04). The gross reproductive rate (GRR) and the proportion of female offspring were higher on T. putrescentiae (GRR = 10.73; ratio of females to males = 0.87). Our study demonstrated that B. dentriticus is a potential predator, developing and reproducing successfully on the two mites T. putrescentiae and M. ginglymura. Blattisocius dentriticus performed better against T. putrescentiae.