Efficiency of Experimental Formulation Containing Duddingtonia flagrans and Pochonia chlamydosporia against Moniezia expansa Eggs.

This study aimed to evaluate the effectiveness of the experimental formulation containing chlamydospores of Duddingtonia flagrans and Pochonia chlamydosporia fungi, against Moniezia expansa. Two experiments were carried out. The first experiment evaluated the in vitro efficacy using 1 g of the experimental formulation (V1) added to 100 M. expansa eggs and the control (V2) (without the fungal formulation). Intact eggs or eggs with alterations were counted in order to evaluate their effectiveness. The second experiment evaluated the action of the fungal formulation on M. expansa eggs after passing through the gastrointestinal tract of goats. Three groups were identified as B1, B2, and B3, which received 1.0, 1.5 g of experimental fungal formulation, and placebo, respectively. In experiment 1, all the eggs in V1 were subjected to the predatory action of fungi, while in V2, the eggs remained intact. In experiment 2, the reduction of eggs in groups B1 and B2 were 49% and 57% 24 h after ingestion, 60% and 63% 48 h after, and 48% and 58% 72 h after. The predatory capacity against M. expansa eggs shown in the tests demonstrated that experimental fungal formulation has the potential to be used on integrated helminth control programs.

Acaricidal activity of carvacrol and thymol on acaricide-resistant Rhipicephalus microplus (Acari: Ixodidae) populations and combination with cypermethrin: Is there cross-resistance and synergism?

This study evaluated the acaricidal activity of thymol and carvacrol on Rhipicephalus microplus populations with different resistance profiles and investigated the synergistic effect of combinations of these monoterpenes with cypermethrin. The adult immersion test (AIT) was used to characterize the susceptibility of tick populations (45 field populations) to synthetic acaricides: deltamethrin, amitraz and chlorfenvinphos. The larval packet test (LPT) was used to determine the LC50 values for thymol (25 tick populations) and carvacrol (20 tick populations). The susceptible strain Porto Alegre (POA) was used as a reference for calculating the resistance ratio (RR). Subsequently, larval immersion tests (LIT) were performed with combinations of cypermethrin with thymol or carvacrol to assess a synergistic effect. In the AIT, deltamethrin showed efficacy > 90% in one (2.2%) population tested (mean: 12.1 and 11.1 for populations 1-25 and 26-40, respectively), whereas amitraz and chlorfenvinphos showed efficacy > 90% for two (4.4%) populations (mean: 61.3 and 47.3 for populations 1-25 and 26-40, respectively) and eight (17.7%) populations (mean: 69.7 and 59.7 for populations 1-25 and 26-40, respectively). In the LPT, the LC50 values for thymol and carvacrol varied from 0.67 to 2.12 mg/mL and 0.55-3.21 mg/mL, with an average LC50 for populations of 1.49 and 1.75 mg/mL, respectively. For thymol, no resistance was observed in any of the populations, values of RR50 > 1.5. There was no correlation between the LC50 values for thymol and the efficacy of the chemical acaricides tested. Regarding carvacrol, for only one tick population had the value of RR50 > 1.5, indicating an incipient resistance. No correlation was observed between the LC50 values for carvacrol and the efficacy of tested acaricides. The combination of thymol and carvacrol with cypermethrin showed a synergistic effect in the resistant population (Jaguar - thymol 4.19 and carvacrol 3.67), and no synergistic interaction were showed in the susceptible population. Answering the questions we conclude that: 1 - The comparison between the LC50 values for thymol and carvacrol in field populations and the susceptible strain POA suggests the absence of cross-resistance (ticks and terpenes), and the differences between the LC50 values for thymol and carvacrol in the different R. microplus populations are inherent to the characteristics of each population tested; 2 - the combination of thymol or carvacrol with cypermethrin showed a synergistic effect with different activity according to the population of ticks.

First report of Caryospora sp. infection in free-living green turtles (Chelonia mydas) in Northeastern Brazil.

Infection by Caryospora cheloniae has been reported to be responsible for green turtle strandings with high morbidity and mortality rates worldwide. Although studies have already shown the pathogenesis of these infections, many aspects of this protozoan are still poorly understood, including their life cycle and infection dynamics in free-living sea turtle populations. Due to the lack of information about the infection by this protozoan in sea turtles in Northeastern Brazil, our study aims to describe Caryospora sp. infection and its pathological findings in free-living Chelonia mydas found on the north coast of the Bahia state. Between 2018 and 2019, 64 specimens of green turtles were necropsied in partnership with Fundação Projeto Tamar; among these, 10 (1.56%) had oocysts morphologically compatible with Caryospora cheloniae in the evaluation of fecal samples and histopathological examination of intestinal samples. The infected animals were juvenile green turtles that were found stranded on the beaches of the north coast of Bahia. The pathological findings were restricted to the lower gastrointestinal tract, with different presentations and intensities. About 70% of the animals with coccidial infection exhibited erosive and ulcerative fibrinous enteritis. This is the first report of coccidiosis in green turtles on the north coast of Bahia.

Effect of the formulation with fipronil and fluazuron on the reproductive biology and ovaries histopathology of Rhipicephalus microplus engorged females.

This study aimed to evaluate the effects of a commercial formulation containing fipronil and fluazuron on the reproductive biology and the morphology of ovaries from Rhipicephalus microplus engorged females. To carry out the study, three calves were artificially infested every 3 days with approximately 5000 larvae. On day 0, the animals were treated with a commercial formulation containing fipronil (1.25 mg/kg) + fluazuron (2.5 mg/kg). Before the application of the acaricide, engorged females of R. microplus were collected to constitute the control group (10 for biology analyses and 20 for histology analyses). After applying the commercial formulation, naturally detached engorged females were recovered on days + 5, + 10, and + 20 (10 engorged females/day) to evaluate their reproductive biology, and on days + 4, + 12, and + 20 (20 engorged females/day) for histological evaluation of the ovaries. Females from the treated groups produced smaller amounts of eggs, exhibiting lower viability when compared to eggs from the control group (p < 0.05). The ovaries of females from all treated groups (+ 4, + 12, and + 20) showed morphological changes, including: cytoplasmic disorganization, cytoplasmic degradation, irregular shape of the oocyte and germinal vesicle, reduction and vacuolization of yolk granules and oocyte disruption. Oocytes were observed in smaller numbers in all stages of development (I, II, III, IV, and V) and greater numbers of indeterminate oocytes were verified in the ovaries of the treated groups when compared to the control group. Therefore, results showed that the commercial formulation containing fipronil and fluazuron affected the reproductive biology, caused morphological changes in the ovaries, and reduced the number of oocytes in R. microplus engorged females.

Association between entomopathogenic nematodes and fungi for control of Rhipicephalus microplus (Acari: Ixodidae).

The aim of the study was to assess the effect of the association of entomopathogenic nematodes and fungi on Rhipicephalus microplus. The nematodes used were Heterorhabditis bacteriophora HP88 and Heterorhabditis indica LPP1 and the fungi were Metarhizium anisopliae IBCB 116 and Beauveria bassiana ESALQ 986. In the groups treated with the fungi, the females were immersed for 3 min in a conidial suspension, while in the groups treated with the nematodes, the ticks were exposed to infective juveniles. To evaluate the interaction between entomopathogens, the females were first immersed in a conidial suspension and then exposed to the nematodes. The egg mass weight and hatching percentage values of the groups treated with M. anisopliae IBCB 116 and B. bassiana ESALQ 986 in the two experiments were statistically similar (p > 0.05) to the values of the control group. In the groups treated only with nematodes, there was a significant reduction (p < 0.05) in the egg mass weight, a fact also observed for the hatching percentage of the group treated with H. indica LPP1. In all the groups treated with nematodes in association with fungi, there was a significant reduction (p < 0.05) in the egg mass weight and hatching percentage. The percentage of control of the groups treated with fungi alone varied from 31 to 55%. In the groups treated with nematodes associated or not with fungi, the control percentage was always greater than 90% and reached 100% in the group treated with H. bacteriophora HP88 associated with the fungus M. anisopliae IBCB 116.