Comparative transcriptional analyzes of Xanthomonas citri subsp. citri reveal mechanisms of adaptation and bacterial virulence in the early stage of citrus canker disease

European Journal of Plant Pathology - The Allium cepa L. (onion) crop is affected by leaf blight disease caused by Stemphylium vesicarium; the shifts that S. vesicarium infection causes in the...     

Characterization of Lay Phase in Three Genetic Types of Heavy Broilers Breeder in Tropical Conditions

The objective of the present work is characterizing some parameters in the lay phase in the lines of heavy broilers breeder Cobb Avian 48, Arbor Acres Plus and Ross 208, reared under the same commercial conditions in the tropics. Monitored three batches of approximately 18,000 females each （one for each genetic type）, from weeks 24 to 64, according to the conditions of handling and power described by the generic lines distribution companies. Although no differences were found for feed intake, Cobb Avian was presented a lower rate of feed conversion, being also that presented the highest percentage of implementation and production of incubables eggs, which meant that it was in line with the highest cumulative production of chickens by bird and week for tropical conditions studied. To adjust the lay data to a Gorssman model, in order to predict the parameters that characterize the lay modeling, estimated the best behavior for Cobb Avian 48 females, because while it takes more time to reach the level of putting constant （5.30 weeks） and maintain it for less time （2.4 weeks）, they manage to put constant high （79.11%） level, considering that the largest number of eggs per bird （171.19 vs. 164.54 and 160.11 in Arbor Acres and Ross 208, respectively）.     

Increased CO2 emission and organic matter decomposition by leaf-cutting ant nests in a coastal environment

Leaf-cutting ants perform a vital role in the cycling of carbon and nutrients in tropical ecosystems. Nests have high levels of organic matter and refuse dumps host up to two times more soil micro-organisms than non-nest soil. The increased levels of organic matter in the soil of nests, however, can affect CO₂ emissions from soil and alter the balance of atmospheric CO₂. We aimed at assessing the effect of nests of the leaf-cutting ant Acromyrmex balzani on CO₂ emissions in a coastal area of Northeast Brazil. Results show that A. balzani nests emitted up to four times more CO₂ than the surrounding soil and emissions were positively correlated with soil moisture and soil organic matter (SOM) content. In addition, field experiments demonstrated that refuse material has a lower residence time than the leaf material brought to the colonies. Despite the high density of nests and high content of SOM compared to adjacent control soil, CO₂ emissions by A. balzani nests represent only 0.3% of the total CO₂ efflux by the studied ecosystem. Although these effluxes account for a relative small portion of the total soil CO₂ emission, they are still important for the understanding of C balance, especially when one considers the thousands of tons of CO₂ emitted each day, across entire Neotropical regions where leaf-cutting ants occur.     

Modelling the progress of Asiatic citrus canker on Tahiti lime in relation to temperature and leaf wetness

The combined effect of temperature (15°C, 20°C, 25°C, 30°C, 35°C, 40°C and 42°C) and leaf wetness duration (0, 4, 8 12, 16, 20 and 24 h) on infection and development of Asiatic citrus canker (Xanthomonas citri subsp. citri) on Tahiti lime plant was examined in growth chambers. No disease developed at 42°C and zero hours of leaf wetness. Periods of leaf wetness as short as 4 h were sufficient for citrus canker infection. However, a longer leaf duration wetness (24 h) did not result in much increase in the incidence of citrus canker, but led to twice the number of lesions and four times the disease severity. Temperature was the greatest factor influencing disease development. At optimum temperatures (25–35°C), there was 100% disease incidence. Maximum disease development was observed at 30–35°C, with up to a 12-fold increase in lesion density, a 10-fold increase in lesion size and a 60-fold increase in disease severity.     

Outbreaks of attacks by hematophagous bats in isolated riverine communities in the Brazilian Amazon: a challenge to rabies control

Human rabies has re-emerged in Latin America due to bat associated transmission. We present data related to attacks by hematophagous bats in three riverine communities in the Rio Negro basin, Brazilian Amazon. A cross-sectional survey was carried out to obtain demographic and epidemiological data through interviews with 201 inhabitants. A total of 721 bat attacks with bites took place from 2004 to 2006, 238 (33%) reported by residents in Campinas do Rio Preto, 329 (46%) in águas Vivas and 154 (21%) in the community of Malalahá. Incidence density among surveyed inhabitants was 84 attacks/100 persons-years in Campinas do Rio Preto, 249 attacks/100 persons-years in águas Vivas and 81 attacks/100 persons-years in Malalahá. The proportion of surveyed inhabitants bled by bats at least once was 67% (63/94) in Campinas do Rio Preto, 96% (42/44) in águas Vivas and 62% (39/63) in Malalahá. Among subjects bled by bats, the average number of bites was 4.6 ± 4.2 standard deviations (SD) in Campinas do Rio Preto, 8 ± 6 SD in águas Vivas and 4.1 ± 3.9 SD in Malalahá. Regarding houses, 67% (26/39) had animals in the peridomestic environment (chickens and/or dogs) and all were vulnerable to bats due to gaps in the walls and/or in the windows and doors. In 13 dwellings, rudimentary protection against bats through the fixation of fishing nets and/or straw nets to the windows and other openings was observed. Among dwellers reporting attacks, 48% (68/144) received the full post-exposure anti-rabies vaccination protocol with five doses of diploid human cell vaccine, 28% (39/144) received an incomplete schedule (1-4 doses), and 26% (37/144) did not receive any dose. No cases of rabies were reported during the study; however, regular pre-exposure vaccination in the studied populations must be considered.     

Evaluation of the effects of performance dentistry on equine rideability: a randomized,blinded, controlled trial

Objective: This study attempted to determine: (1) if degree of dental malocclusion assigned prior to dental treatment was associated with equine rideability, assessed using a standardized score and (2) if performance dentistry improved this score.

Animals: Thirty-eight Franches-Montagnes stallions.

Methods: All horses were examined and assigned a dental malocclusion score by a veterinary dentist and randomized into two groups: sham treatment (Group S) and performance dentistry including occlusal equilibration (Group D). The horses were ridden twice before and three times after treatment by a professional dressage rider (unaware of treatment allocation). The horses were assigned a rideability score using a 27-point scale. The malocclusion score was compared to the average of the first two rideability scores using Spearman's coefficient of rank. Change in rideability scores over time was assessed by repeated measures ANOVA. Statistical significance was set at P < 0.05.

Results: There was no correlation between dental score and rideability score prior to treatment (r_s = 0.06, P = 0.73). In addition, there were no differences in the rideability score between treatment groups or as an interaction of treatment group and time (P = 0.93, P = 0.83, respectively).

Conclusions: In conclusion, we were unable to show that performance dentistry improved equine rideability assessed by rider scoring. The addition of more objective measurement tools and a longer assessment period may help to scientifically prove what is anecdotally believed.     

A wide diversity of zoonotic intestinal parasites infects urban and rural dogs in Neuquén,Patagonia, Argentina

The presence of parasites was investigated by the examination of 1944 dog faecal samples collected from urban (n = 646) and rural (n = 1298) areas of the province of Neuquén, Patagonia, Argentina. Parasitic agents (PA) were found in 37.86% of samples. A total of 15 different PA were detected, including Toxocara canis (16.35%), Taenia spp./Echinococcus spp. (12.65%), Trichurisvulpis (6.06%), Giardia spp. (1.29%), Toxascaris leonina (0.56%), Ancylostomacaninum (0.41%), Dipylidium caninum (0.31%), Diphyllobothrium spp. (0.10%), among others. Several of these PA are recognized as zoonotic agents. Therefore, the results of this investigation revealed that local population is exposed to a broad spectrum of zoonotic parasites by means of environmental contamination with dog faeces. Prevalence of PA was slightly higher in rural (40.06%) than in urban (33.44%) locations. Distribution of groups of PA (cestodes, nematodes, and protozoa) showed statistical differences between both habitats. Prevalence of cestodes (18.18%) and protozoa (11.86%) was significantly higher in the rural environment than in urban areas and nematodes (29.10%) were more frequent in urban locations. Infection of dogs with Linguatula serrata and Cryptosporidium sp. was demonstrated for the first time in Neuquén. Rural dogs of the study area are under hydatic disease control program, which includes treatment with praziquantel every 6 weeks; thus, the finding of high level of cestode infection in these areas is of great relevance. The epidemiology of zoonotic parasitic infections in urban and rural dogs showed different patterns and, in consequence, different control measurements should be applied in each location.     

Mercury in the Aquatic Environment of the Village of Caimito at the Mojana Region,North of Colombia

During May–September 1999, several aquatic environmental samples were collected from the village of Caimito, in the San Jorge River basin area, state of Sucre (Colombia), and analyzed for total mercury (T-Hg). Mean T-Hg concentration in sediments from surrounded marshes was 0.155 ± 0.016 g Hg/g. Low Hg concentrations were found in the phytoplanktivorous fish species Prochilodus magdalenae (0.087 ± 0.01 g Hg/g), while four-fold greater concentrations were found in all the carnivorous species. In average, T-Hg concentrations for fish samples did not exceed the limit consumption level (0.5 g Hg/g). However, risk assessment based on the hazard index suggested that the consumption of 0.1 kg per day of carnivorous fish could increase the risk of mercury poisoning in local population.     

Clinical and serological aspects of visceral leishmaniasis in northeast Brazilian dogs naturally infected with Leishmania chagasi

Human visceral leishmaniasis is endemic in the northeast of Brazil, where the domestic dog is an important parasite reservoir in the infectious cycle of Leishmania chagasi. In this study, we evaluated the clinical signs of canine visceral leishmaniasis (CVL), serum protein profile and the antileishmanial IgG antibody production in 86 dogs living in northeast endemic areas of leishmaniasis. Thirty dogs from a leishmaniasis-free area were used as a control group. The major clinical signs of CVL seen were emaciation and skin ulcers (80%), followed by onychogryphosis and conjunctivitis (73%). Depilation was observed in 60% of animals while lymphadenomegaly, splenomegaly, liver enlargement or kidney involvement was less frequent (< or =20%). VL seropositive dogs presented with serum hyperproteinemia, hypoalbuminemia, hypergammaglobulinemia and decreased albumin/globulin ratio. A lower sensitivity and higher specificity was observed for promastigote indirect fluorescent antibody test (IFAT) (83 and 100%, respectively) compared with enzyme-linked immunosorbent assay (ELISA) (94 and 90%), which uses a crude extract of Leishmania. There was a positive correlation between IFAT and ELISA titers of antileishmanial IgG antibodies (Spearman test, P < 0.05), which was augmented in CVL dogs. This study found that the determination of serum protein, A/G ratio and the use of two different leishmanial serological tests like IFAT and ELISA are essential in CVL screening.