Influence of climatic and management factors on Eimeria infections in goats from semi-arid zones

A survey of Eimeria infections was performed in dairy goats and kids (<6 months old) of six farms from a dry desert area of Gran Canaria Island (Spain). The number of oocysts per gram of faeces (OPG) was determined by a modified McMaster technique over a total of 2,616 individual faecal samples taken from the rectum in monthly intervals. Eimeria oocysts were found in 96.1% of the samples with OPG ranging from 1 x 10(2) to 1.4 x 10(6). Kid goats had significantly (P < 0.001) higher OPG counts (46,496 +/- 5,228) than dairy females (2,225 +/- 287). Eight Eimeria species were identified, with Eimeria ninakohlyakimovae (30.0%), Eimeria arloingi (28.6%) and Eimeria alijevi (20.5%) being the most frequent species followed by Eimeria caprina (9.1%), Eimeria christenseni (4.5%), Eimeria jolchijevi (3.4%), Eimeria caprovina (3.2%) and Eimeria hirci (0.7%). Although significant differences were observed among goat groups and herds, the eight species were present in the six farms in both dairy goats and kids. The intensity of oocysts shedding was related to some factors such as the size of the herd and was further influenced by the prevailing climatic conditions of the area. The highest OPG counts were recorded during the hot season in dairy goats and close to weaning time in kids reared in small farms having no prophylactic treatments against eimeriosis.     

An immunocytochemical procedure for protein localization in various nematode life stages combined with plant tissues using methylacrylate-embedded specimens

Plant-parasitic nematodes possess a large number of proteins that are secreted in planta, allowing them to be successful parasites of plants. The majority of these proteins are synthesized mainly in the nematode subventral and dorsal glands as well as in other organs. To improve the immunovisualization of these proteins, we adapted a methacrylate embedding method for the localization of proteins inside nematode tissues, and extracellularly when secreted in planta or within plant cells. An important advantage is that the method is applicable for all nematode stages: preparasitic as well as parasitic stages, including large mature females. Herein, the method has been successfully applied for the localization of four nematode secreted proteins, such as Mi-MAP-1, Mi-CBM2-bearing proteins, Mi-PEL3, and Mi-6D4. In addition, we could also localize 14-3-3 proteins, as well as two cytoskeletal proteins, by double-immunolabeling on preparasitic juveniles. Superior preservation of nematode and plant morphology, allowed more accurate protein localization as compared with other methods. Besides excellent epitope preservation, dissolution of methacrylate from tissue sections unmasks target proteins and thereby drastically increases antibody access.     

Biometrical, biological, biochemical and molecular characteristics of Meloidogyne incognita isolates and related species

Meloidogyne incognita is one of the most polyphagous species of root-knot nematodes occurring in Brazil and worldwide. Eight M. incognita isolates were studied, representing two enzymatic phenotypes (esterase and malate desydrogenase: I1/N1, I2/N1) and four cryptic Meloidogyne sp.1 (S2/N1) isolates, representing one cytological type (3n?=?40–46). Three M. hispanica isolates (Hi3/N1, 2n?=?32–36) and two of an atypical Meloidogyne sp.2 (S2a/N3, 3n?=?40–44) were included in this study for comparison. All isolates were tested with three M. incognita-specific molecular markers. The primer pairs B06F/R, miF/R and incK14F/R amplified three species-specific fragments of 1,200?bp, 955?bp and 399?bp, respectively for M. incognita and Meloidogyne sp.1 isolates. No amplification occurred in the M. hispanica and Meloidogyne sp.2 isolates, except with primers miF/R (1,650?bp). The genetic variability of the Meloidogyne spp. isolates was evaluated, using RAPD and ISSR markers. The phylogenetic analyses revealed two strongly supported monophyletic clades: clade I, consisting of M. hispanica and the atypical Meloidogyne sp.2 isolates, and clade II, clustering together all M. incognita and the Meloidogyne sp.1 isolates. Considering the biometrical, cytological and molecular approaches, it was possible to conclude that the isolates with three enzymatic phenotypes (I1/N1, I2/N1 and S2/N1) presented the characteristics described for M. incognita. Some correlations were detected between the isozymatic phenotypes and the tree topology (S2a/N3, Hi3/N1, I1/N1, S2/N1), but no strict correlation could be observed for the phenotype I2/N1 and one isolate of S2/N1. Morphologically, the Msp.2 isolates differ from M. incognita and M. hispanica by the female stylet features presenting straight cone tip and round pear shaped knobs, posteriorly sloping. The results of this study suggested that the Msp.2 isolates with phenotypes S2aN3 belong to a new or an unidentified species closely related to M. hispanica.     

Postharvest water relations in cut rose cultivars with contrasting sensitivity to high relative air humidity during growth

A constant high relative air humidity (RH) during cultivation can strongly reduce the vase life in some cut rose cultivars. We studied three contrasting cultivars in their tolerance to high RH in order to analyse in detail the water relations during postharvest and better understand this genotypic variation. Plants were grown at moderate (60%) and high (95%) RH, and cut flowers were placed in water immediately after cutting. Flowers of cv. Pink Prophyta grown at high RH did not open throughout vase life, while flower opening of cvs. Frisco and Dream was not affected by preharvest RH. Cultivation at high RH resulted in about 80% shorter vase life in Pink Prophyta, whereas in Dream and Frisco the negative effect was considerably smaller (15 and 9% shorter vase life, respectively). The shorter vase life and reduced flower opening of cut roses grown at high RH was due to a higher rate of transpiration both in the light and dark periods. It was found that the leaves of Pink Prophyta grown at high RH could partly close their stomata upon lowering of the water potential or when flower stalks were fed with abscisic acid, but stomata remained far more open than in leaves grown at moderate RH. The RH during cultivation did not affect stem hydraulic conductivity and its recovery after air emboli induction. Preventing vascular occlusion largely alleviated the high-cultivation-RH effect on vase life and flower opening, showing that the effect of high-cultivation-RH becomes only important if water uptake is limited.     

Vaccine immune response and interference of colostral antibodies in calves vaccinated against rabies at 2, 4 and 6 months of age born from antirabies revaccinated females

Considering the high prevalence of rabies in cattle, we aimed to evaluate the interference of colostral antibodies transferred to calves after birth and the benefit of administering an antirabies vaccination in two-month-old calves compared to vaccinating at 4 and 6 months of age. Calves born from females revaccinated against rabies during the third trimester of pregnancy were studied. Forty-eight hours after parturition, blood samples from dams and offspring were collected, and antirabies neutralizing antibody titers were analyzed using the Rapid Focus Fluorescent Inhibition Test. We found that all calves had similar titers of antibodies transferred through the colostrum. Furthermore, none of the calves presented a satisfactory serological response after the first vaccination, but all had an appropriate response after revaccination. This study demonstrates that antirabies vaccination should be recommended for calves at two months of age in endemic and epizootic situations.     

Update on the role of innate immune receptors during Brucella abortus infection

The innate immune system constitutes an efficient defense mechanism against invading microbial pathogens. Recent studies have revealed the intracellular signaling cascades involved in the TLR-initiated immune response to Brucella spp. infection. However, there is a piece of the puzzle missing that is the role of non-TLR receptors in innate immunity. The involvement of TLR receptors in brucellosis has been investigated by different research groups. It was demonstrated that TLR2 clearly does not play any role in controlling Brucella abortus infection in vivo, whereas TLR9 has been shown to be required for clearance of this bacterium in infected mice. The participation of adaptor molecules, such as MyD88 and TRIF has also been discussed. Recently, we and others have reported the critical role of MyD88- and not TRIF-mediated signaling in dendritic cell maturation and in vivo resistance during B. abortus infection. However, the relationship between specific Brucella molecules and non-TLR receptors and signal transduction pathways needs to be better understood. It is now clear that the interaction between TLRs and recently identified cytosolic innate immune sensors is crucial for mounting effective immune responses. Finally, this review discusses the mechanisms used by Brucella to escape detection by the host innate immune system.     

Risk factors for avian influenza and Newcastle disease in smallholder farming systems, Madagascar highlands

Newcastle disease (ND) and avian influenza (AI) are issues of interest to avian producers in Madagascar. Newcastle disease virus (NDV) is the major constraint for village aviculture, and avian influenza viruses type A (AIAV) are known to circulate in bird flocks. This study aims at classifying smallholder poultry farms, according to the combination of risk factors potentially associated with NDV and AIAV transmission and to assess the level of infection for each farm class. Two study sites, Lake Alaotra and Grand Antananarivo, were chosen with respect to their differences in terms of agro-ecological features and poultry productions. A typology survey involving 526 farms was performed to identify possible risk factors for (i) within-village, and (ii) between-village virus transmission. A cross-sectional serological study was also carried out in 270 farms to assess sero-prevalences of NDV and AIAV for each farm class and the link between them and risk factor patterns. For within-village transmission, four classes of farms were identified in Grand Antananarivo and five in Lake Alaotra. For between-village virus transmission, four classes of farms were identified for each site. In both sites, NDV sero-prevalence was higher than for AIAV. There was no evidence of the presence of H5 or H7 subtypes of AIAV. Sero-prevalences were significantly higher in Lake Alaotra than in Grand Antananarivo for both viruses (OR=2.4, p=0.02 for NDV, and OR=9.6, p<0.0001 for AIAV). For within-village NDV transmission in Grand Antananarivo, backyard chicken farms (OR=3.6, p<0.001), and chicken farms with biosecurity awareness (OR=3.4, p<0.01) had greater odds of having antibodies against NDV than the others. For between-village virus transmission, farms with multiple external contacts, and farms using many small markets had greater odds of having antibodies against NDV than the others (OR=5.4, p<0.01). For AIAV, there were no differences in sero-prevalences among farm classes. In Lake Alaotra, the observed high density of palmipeds and widespread rice paddies were associated with high sero-prevalences for both viruses, and a homogeneous risk of virus transmission between the different farm classes. In Grand Antananarivo, farm visits by collectors or animal health workers, and farm contacts with several markets were identified as potential risk factors for NDV transmission. Further studies are needed to identify the circulating virus genotypes, model their transmission risk, and provide adapted control measures.     

Gene expression and immunolocalization of fibroblast growth factor 2 in the ovary and its effect on the in vitro culture of caprine preantral ovarian follicles

This study quantified Fibroblast growth factor 2 (FGF-2) mRNA and localized FGF-2 protein in different categories of follicles isolated from goat ovaries. In addition, we verified the effects of this factor on the in vitro culture of preantral follicles isolated from goats. For mRNA quantification, we performed real-time PCR using primordial, primary and secondary follicles, as well as cumulus-oocyte complexes (COCs) and mural granulosa and theca cells of small and large antral follicles. For FGF-2 protein localization, the ovaries were subjected to conventional immunohistochemical procedures. Preantral follicles were isolated and cultured in vitro for 12 days in either control (basic) or supplemented with FGF-2 medium. The expression of FGF-2 mRNA was detected in all categories of follicles and there was no difference in preantral follicles and COCs or granulosa/theca cells from small and large antral follicles. However, in large antral follicles, COCs showed expression levels significantly lower than in granulosa/theca cells (p < 0.05). We observed moderate expression of FGF-2 protein in preantral follicles but not in granulosa cells of primordial follicles and theca cells of secondary follicles. In both small and large antral follicles, strong, moderate and weak staining was observed in oocytes, granulosa and theca cells, respectively. The addition of FGF-2 caused a significant increase in the daily follicular growth rate compared to the control group. We conclude that FGF-2 mRNA is expressed throughout follicular development and that its protein can be found in different patterns in preantral and antral follicles. Furthermore, FGF-2 increases the follicular growth rate in vitro.     

The effect of LIF in the absence or presence of FSH on the in vitro development of isolated caprine preantral follicles

We investigated the effect of the leukaemia inhibitory factor (LIF) alone or in association with FSH on the in vitro culture (IVC) of caprine preantral follicles. Preantral follicles >200 μm in size were isolated and cultured for 18 days in basic medium either alone (control) or supplemented with LIF (10 or 50 ng/ml) in the absence or presence of FSH. Every 6 days, follicular survival, growth and antrum formation were evaluated. At the end of the culture period, the oocytes underwent in vitro maturation (IVM), and their viability and chromatin configuration were assessed. Follicles of the control group and those cultured in 10 ng/ml LIF maintained the structural integrity (particularly the preservation of the basement membrane) when compared to the oocytes cultured in 50 ng/ml LIF, regardless the presence of FSH. In the absence of FSH, the percentage of antrum formation after 18 days of culture in the 50 ng/ml LIF group was significantly lower than in either the control group or the 10 ng/ml LIF group. However, this effect was not observed in the presence of FSH. The rate of resumption of meiosis was significantly higher in the 50 ng/ml LIF group in the absence of FSH in comparison with the control and 10 ng/ml LIF groups. Metaphase II was observed only when follicles were cultured in a combination of FSH and 50 ng/ml LIF. In conclusion, LIF alone does not interfere with antral formation and oocyte growth, but at concentration of 50 ng/ml and combined with FSH, it promotes oocyte maturation.