Guilherme Liberato da Silva

Rhipicephalus sanguineus (ACARI: IXODIDAE) BITING A HUMAN BEING IN PORTOALEGRE CITY, RIO GRANDE DO SUL, BRAZIL.

We report the finding of a female brown dog tick, Rhipicephalus sanguineus (Acari: Ixodidae) on the scalp of a male patient in Porto Alegre, Rio Grande do Sul, Brazil. Human parasitism by this tick is rare and has seldomly been reported in the literature, despite its recognized importance since it can act as a vector of Rickettsia rickettsii, the agent of spotted fever.

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.

The ectoparasites Dermanyssus gallinae and Megninia ginglymura: bioecology and natural enemies in commercial egg-laying hens

Abstract Egg-laying hens and free and wild birds may introduce pathogenic organisms and ectoparasites to farms linked to commercial poultry farm systems. Two mite species are reported as an economic problem for the poultry industry worldwide: Dermanyssus gallinae (Dermanyssidae) and Megninia ginglymura (Analgidae). The present study aimed to evaluate the bioecology of mite fauna especially D. gallinae and M. ginglymuraassociated with commercial egg-laying hens, and recognize which are infestation periods, favorable environments and efficient predators of these ectoparasites. Megninia ginglymura was the most abundant in feathers and more frequent in the battery cage than in free-range chickens, representing 98% of the species. Both of these husbandry systems showed high infestations at different times. On the other hand, D. gallinae was the most abundant species in traps (98.9%), being found mostly in the winter from free-range chickens, with more than twice the mites when compared with battery cage chickens. This work revealed a possible new tool for biological control of ectoparasites: Cheyletus malaccensis could be considered the main natural enemy with the best potential for controlling these ectoparasites associated with laying hens and should be taken into consideration for future biological control studies, becoming an additional strategy for controlling D. gallinae principally.

Dermatitis caused by the tropical fowl mite Ornithonyssus bursa (Berlese) (Acari: Macronyssidae): a case report in humans

We herein report human dermatitis caused by the tropical fowl mite Ornithonyssus bursa (Berlese). The cases occurred in an apartment in a residential district of Porto Alegre City, State of Rio Grande do Sul, Brazil, where three members of the same family presented with pruritic lesions on the arms and legs. On inspecting the bathroom, several mites measuring approximately 1.0mm in length were observed coming from a nest of Rufous Hornero, Furnarius rufus (Gmelin). This is the first report of O. bursa in the urban area of Porto Alegre City, from a nest of F. rufus that bites humans.

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.

Mite fauna associated with bird nests in Southern Brazil

Abstract Interactions between birds and mites have allowed mites to act as ectoparasites or to be associated with the micro-environments of nests. The aim of this study was to identify the mite fauna associated with wild bird nests in the rural and urban zones of different environments, and analyze the importance of birds as potential carriers of these organisms to households or poultry houses. In the rural zone, the following environments were assessed: Countryside (C), Forest (F), Aquatic (A), Orchards (O), and Residential (R), and in the urban zone, a similar division was used (C, O, R), with absence of environments (A) and (F). Apart from the Suborder Oribatida found in the 52 bird nests sampled in both zones, a total of 24,274 mites were collected and identified as 67 species in 34 families. There was a predominance of mites in the rural zone (90%), with higher richness in (C) of both zones and higher abundance in (R) and (A) of the rural zone and (O) of the urban zone. Mite species of medical-veterinary importance with the highest abundance were Ornithonyssus bursa in nests of Certhiaxis cinnamomeus and Columbina picui; Tyrophagus putrescentiae in nests of Columbina picui and Pitangus sulphuratus; and Dermatophagoides pteronyssinus in nests of Troglodytes musculus and Pitangus sulphuratus. This study showed that the wild bird nests are depositories of mites, including ectoparasites of medical-veterinary importance.

Life cycle of the predatory mite Cheyletus malaccensis (Acari: Cheyletidae) fed on Poultry Red Mite Dermanyssus gallinae (Acari: Dermanyssidae)

Abstract This study evaluated the biological characteristics of predatory mite Cheyletus malaccensis fed on Dermanyssus gallinae at different temperatures. The study started with thirty individual eggs of C. malaccensis each isolated in an experimental unit, which developed throughout their life stages while feeding on D. gallinae at each temperature tested (20ºC, 25ºC and 30±1ºC and 80±5% relative humidity). Emerged adult females were not mated, thus producing only male offspring (arrhenotoky). Fecundity was the highest at 25°C (415.62±24.78 eggs/female) and lowest at 20°C followed at 30ºC. The mean length of a generation did not displayed difference among the three temperatures, but the net reproductive rate (Ro), innate capacity for increase (rm) finite increase rate (λ) were significantly higher at 30°C and lower at 20°C. Cheyletus malaccensis was able to develop and reproduce successfully when fed D. gallinae, and the optimum temperature for development, fertility and survival was 25°C. Our findings proved that C. malaccensis might be a natural enemy of D. gallinae, because it was able to develop and reproduce while feeding exclusively on this ectoparasite.

First description of iolinid mites (Acari: Tydeoidea) from Brazil

Abstract The family Iolinidae is recorded from Brazil for the first time. Two new species: Pausia litchiae n. sp. and Pseudopronematulus nadirae n. sp. collected from leaves of Litchi chinensis Sonn. (Sapindaceae) at Viçosa County, Minas Gerais State are described and illustrated.

Development of Cheyletus malaccensis (Acari: Cheyletidae) feeding on mite species found in commercial poultry systems: Megninia ginglymura (Acari: Analgidae) and Tyrophagus putrescentiae (Acari: Acaridae)

Abstract Intensive egg production affects the welfare of confined laying hens, which increases the risk of epidemics. Ectoparasitic hematophagous mites and saprophagous feather mites cause low productivity and decreased egg quality. This study aimed to compare the biology of Cheyletus malaccensis (Oudemans) (Prostigmata: Cheyletidae) feeding on the prey Megninia ginglymura (Mégnin) (Astigmata: Analgidae) and Tyrophagus putrescentiae (Schrank) (Astigmata: Acaridae) in order to support the potential use of this predator in biological control strategies in the poultry industry. The study started with 30 eggs of C. malaccensis, isolated in experimental units, which developed into their different stages while feeding on the feather mite M. ginglymura and the stored product mite T. putrescentiae at 25±1°C, 80±5% relative humidity and 12-hour photoperiod. Immature stages were evaluated three times a day and the adult stage once a day. Adult females were unmated. Cheyletus malaccensis feeding on M. ginglymura resulted in a higher fertility rate, with 310.7±45.8 eggs/female, than with T. putrescentiae as prey, with 32.7±4.5 eggs/female. Furthermore, the oviposition period was higher feeding on M. ginglymura, 53.0±6.3 days, than on T. putrescentiae, 12.6±1.9 days. The net reproductive rate (Ro), the innate capacity for increase (rm), the mean generation time (T) and the finite rate of increase (λ) were higher for the generation fed on M. ginglymura. Cheyletus malaccensis is a likely natural enemy of M. ginglymura, and it is able to develop and reproduce while feeding exclusively on it.

The impact of insecticides management linked with resistance expression in Anopheles spp. populations

The resistance of some species of Anopheles to chemical insecticides is spreading quickly throughout the world and has hindered the actions of prevention and control of malaria. The main mechanism responsible for resistance in these insects appears to be the target site known as knock-down resistance (kdr), which causes mutations in the sodium channel. Even so, many countries have made significant progress in the prevention of malaria, focusing largely on vector control through long-lasting insecticide nets (LLINs), indoor residual spraying and (IRS) of insecticides. The objective of this review is to contribute with information on the more applied insecticides for the control of the main vectors of malaria, its effects, and the different mechanisms of resistance. Currently it is necessary to look for others alternatives, e.g. biological control and products derived from plants and fungi, by using other organisms as a possible regulator of the populations of malaria vectors in critical outbreaks.