Experimental infection by capillary tube feeding of Rhipicephalus sanguineus with Bartonella vinsonii subspecies berkhoffii

It has been speculated that ticks may serve as vectors of Bartonella species. Circumstantial, clinical, epidemiological and serological evidence suggest that B. vinsonii subspecies berkhoffii (B. v. berkhoffii) might be transmitted by Rhipicephalus sanguineus. The purpose of the present study was to determine whether adult R. sanguineus ticks can be infected with a B. v. berkhoffii genotype II isolate via capillary tube feeding and whether the infection can then be transmitted from adult females to their eggs via trans-ovarial transmission. Furthermore, tick fecal material was also collected and screened as a possible source of infectious inoculum for canine infections. B. v. berkhoffii DNA was detected in 50% (7 of 14) of females that did not oviposit and in 14.3% (2 of 14) of female ticks that laid eggs, but not detected in egg clutches (100 eggs/female). DNA was also detected in tick feces collected on days 2 through 6 post-capillary tube feeding, however, dogs (n=3) did not become bacteremic or seroconvert when inoculated with tick fecal material. Therefore, trans-ovarial transmission of B. v. berkhoffii by R. sanguineus is unlikely, but further studies are needed to determine if tick fecal material can serve as a source of infection to canines.     

Efficacy of major anthelmintics against horse cyathostomins in France

This paper reports a survey conducted in France during 2011 to evaluate the efficacy of commonly used anthelmintics against horse cyathostomins. A total of 40 farms and 1089 horses were screened for the presence of cyathostomins. All farms but one were positive, with an overall animal infection rate of 53.7%, ranging from 9% to 83% on individual farms. On 445 horses from 30 of these farms, a faecal egg count reduction test (FECRT) was performed to evaluate the efficacy of oral formulations of fenbendazole (FBZ), pyrantel embonate (PYR), ivermectin (IVM) and moxidectin (MOX). Calculation of the mean FECR and 95% confidence intervals (95% CI) around the mean was performed using bootstrap analysis. Resistance to FBZ was found on 17 of 18 farms investigated, with a mean reduction of 57% (95% CI: 38.5-71.2%). Suspected resistance for PYR was found on 6 of 30 farms, and confirmed on another 3 of 30 farms, with a mean reduction for PYR of 94.7% (95% CI: 88.9-98.5%). Reduced efficacy simultaneously of FBZ and PYR was found in 7 farms. Reduced efficacy of IVM was found in one animal on one farm and of MOX in one animal on another farm, and was combined with resistance against FBZ and/or PYR. These results indicate that single and multiple drug resistance and reduced efficacy in equine cyathostomins is present in France. Macrocylic lactones proved to be highly effective compounds against cyathostomins, with reduced efficacy for IVM and MOX in two farms only. These results extend present knowledge on the occurrence of drug resistant cyathostomins in Europe, and illustrate the necessity to use anthelmintics in appropriate worm control programmes.     

Study on NO regulation of the lymphatic stomata in mice and the mechanism of ultrafiltration failure during peritoneal dialysis

AIM: To study the regulatory effect of nitric oxide on the lymphatic stomata and probe into the mechanism of ultrafiltration failure during long-term peritoneal dialysis(PD). METHODS: ①Sodium nitroprusside(SNP) and N^G-monomethyl-L-arginine(L-NMMA)(inhibitor of nitric oxide synthase(NOS)) were injected into the peritoneal cavity of the mouse model of PD. ②NO concentration was measured in serum. ③The lymphatic stomata was studied with SEM and computer image processing.RESULTS: During PD, a lot of macrophages wandered out of the lymphatic stomata to form milky spots on the peritoneal mesothelium, and the diameter and density of the stomata were increased with NO concentration raised. After PD cessation, the stomata was normal gradually and numbers of milky spots reduced with NO concentration fall. The diameter and density of the stomata were increased with a rise in NO concentration as SNP was used, oppositely those were decreased with the increase in NO concentration as L-NMMA was injected intraperitoneally. CONCLUSIONS: The lymphatic stomata might be regulated through increasing the endogenous NO concentration. During PD, NO is increased gradually and the ultrafiltration failure would occur when re-absorption of the stomata was increased from the peritoneal cavity.     

Influence of porcine intestinal pH and gastric digestion on antigenicity of F4 fimbriae for oral immunisation

Newly weaned piglets can be orally immunised against F4+ enterotoxigenic Escherichia coli (ETEC) infection with F4 fimbriae. However, to efficiently develop a vaccine against ETEC induced postweaning diarrhoea, knowledge of the stability of the F4 fimbriae to different pH and gastric digestion is needed. The gastrointestinal pH in suckling and recently weaned piglets was measured and the stability of F4 fimbriae to different pH and to pepsin was assessed in vitro. In the stomach the lowest pH was found in the fundus gland region. Gastric pH values below 2.5 were not found in suckling piglets or at the day of weaning, in contrast to piglets 1 and 2 weeks postweaning. Along the first half of the small intestine and in the caecum, a negative correlation was found between pH and age. The F4 fimbriae were stable to pH 1.5 and 2 for 2 h, whereas longer incubation periods resulted in conversion of the multimeric forms into monomers. The F4 fimbriae were partially degraded by incubation for 15-30 min in simulated gastric fluid at pH 1.5 and 2, and completely digested from 3 h onwards. At pH 3, the fimbriae maintained their antigenicity for at least 4h. The results demonstrate that gastric digestion will only have a limited impact on oral immunisation since liquid passes through the stomach relatively quickly (50% within 2 h). However, we previously demonstrated that the transit times are prolonged shortly after weaning. Shortly after weaning it could be necessary to protect the F4 fimbriae against gastric digestion to obtain efficient oral immunisation of the piglets.     

Opportunities for domesticating the African baobab (Adansonia digitata L.): multi-trait fruit selection

Among the priority species identified for domestication in the Sahel region of Sub-Sahara Africa is the baobab (Adansonia digitata L.) tree. The quantification of the variation in nutrient content and fruit morphological traits of trees is one of the most important steps in identifying superior planting material for domestication. Ten provenances in Mali covering all the different agro-ecological zones were selected and the fruit morphological traits, vitamin C, calcium, iron and colour were studied. Mean pulp content was 2,149 ± 1,117 , 2,406 ± 776  and 25 ± 17 mg kg^?1 for vitamin C, calcium and iron, respectively. Fruit pulp colour varied from white, creamy to pink and a significant correlation between pulp vitamin C content and reflectance in the green and blue bands was observed. Significant negative correlations were found between rainfall and pulp vitamin C content and between mean annual temperature and fruit and pulp weight and pulp fraction, suggesting that these traits are influenced by the environment. Pulp iron content correlated positively with topsoil sodicity and base saturation. Similarly, pulp vitamin C content correlated positively with topsoil sand fraction. Pulp reflectance in the blue and green bands correlated negatively with topsoil pH water and base saturation, respectively. The variation in nutritive and morphological traits offers the opportunity for selecting plus trees with a combination of desired traits for domestication.     

Naltrexone does not affect isoflurane minimum alveolar concentration in cats

ObjectiveTo test whether naltrexone, an opioid receptor antagonist, affects the minimum alveolar concentration (MAC) of isoflurane in cats, a species that is relatively resistant to the general anesthetic sparing effects of most opioids.Study designRandomized, crossover, placebo-controlled, blinded experimental design.AnimalsSix healthy adult cats weighing 4.9 ± 0.7 kg.MethodsThe cats were studied twice. In the first study, baseline isoflurane MAC was measured in duplicate. The drug (saline control or 0.6 mg kg^?1 naltrexone) was administered IV every 40–60 minutes, and isoflurane MAC was re-measured. In the second study, cats received the second drug treatment using identical methods 2 weeks later.ResultsIsoflurane MAC was 2.03 ± 0.12% and was unchanged from baseline following saline or naltrexone administration.Conclusion and clinical relevanceMinimum alveolar concentration was unaffected by naltrexone. Because MAC in cats is unaffected by at least some mu-opioid agonists and antagonists, spinal neurons that are directly modulated by mu-opioid receptors in this species cannot be the neuroanatomic sites responsible for immobility from inhaled anesthetics.     

Snow gliding and loading under two different forest stands: a case study in the north-western Italian Alps

The presence of a thick snowpack could interfere with forest stability, especially on steep slopes with potential damages for young and old stands. The study of snow gliding in forests is rather comple...     

Evaluation of five serological tests for the diagnosis of porcine brucellosis in French Polynesia

Porcine brucellosis due to Brucella suis biovar 1 raises important issues for pig breeders in French Polynesia. In this region, the disease is enzootic, spreads silently and engenders economic losses in infected farms as well as sporadic human cases. While serological tests are essential in surveillance and control programmes of animal diseases, to date none of the available tests have been shown to be reliable enough to be used as a gold standard in routine individual diagnosis of porcine brucellosis. Few studies about the estimation of the sensitivity and the specificity of porcine brucellosis screening tests have been published, none of them dealing with French Polynesia. The studied population included 1,595 pigs from French Polynesia. Five tests were evaluated: Rose Bengal test, fluorescence polarisation assay, indirect ELISA, and two competitive ELISAs (C-ELISA). The sensitivity and the specificity of each test were estimated. C-ELISA₂ was the most sensitive test (Se C-ELISA₂?=?0.954 [0.889; 0.992] 95 % credibility interval (CrI)) while both C-ELISA and Rose Bengal test (RBT) were the most specific ones (Sp C-ELISA₁?=?0.856 [0.806; 0.915] 95 % CrI; Sp C-ELISA₂?=?0.849 [0.817; 0.879] 95 % CrI; Sp RBT?=?0.853 [0.812; 0.898] 95 % CrI).     

Geospatial variation of physical attributes and sugarcane productivity in cohesive soils

Precision Agriculture - Sugarcane productivity is highly variable across space, and knowledge about the spatial distribution of soil physical attributes is important to guide management practices...