Feline leukaemia. ABCD guidelines on prevention and management

OverviewFeline leukaemia virus (FeLV) is a retrovirus that may induce depression of the immune system, anaemia and/or lymphoma. Over the past 25 years, the prevalence of FeLV infection has decreased considerably, thanks both to reliable tests for the identification of viraemic carriers and to effective vaccines.InfectionTransmission between cats occurs mainly through friendly contacts, but also through biting. In large groups of non-vaccinated cats, around 30–40% will develop persistent viraemia, 30–40% show transient viraemia and 20–30% seroconvert. Young kittens are especially susceptible to FeLV infection.Disease signsThe most common signs of persistent FeLV viraemia are immune suppression, anaemia and lymphoma. Less common signs are immune-mediated disease, chronic enteritis, reproductive disorders and peripheral neuropathies. Most persistently viraemic cats die within 2–3 years.DiagnosisIn low-prevalence areas there may be a risk of false-positive results; a doubtful positive test result in a healthy cat should therefore be confirmed, preferably by PCR for provirus. Asymptomatic FeLV-positive cats should be retested.Disease managementSupportive therapy and good nursing care are required. Secondary infections should be treated promptly. Cats infected with FeLV should remain indoors. Vaccination against common pathogens should be maintained. Inactivated vaccines are recommended. The virus does not survive for long outside the host.Vaccination recommendationsAll cats with an uncertain FeLV status should be tested prior to vaccination. All healthy cats at potential risk of exposure should be vaccinated against FeLV. Kittens should be vaccinated at 8–9 weeks of age, with a second vaccination at 12 weeks, followed by a booster 1 year later. The ABCD suggests that, in cats older than 3–4 years of age, a booster every 2–3 years suffices, in view of the significantly lower susceptibility of older cats.     

Masculinization of the Native Bay Snook,Petenia splendida,Using Oral Administration of the Synthetic Steroid 17α‐methyltestosterone

The possibility of inducing sex reversal in bay snook, Petenia splendida, was evaluated to generate a protocol aimed at producing single‐sex populations (100% males) and improving farming conditions for this species. This popular staple food is a cichlid fish native to Central America, with aquaculture potential. We evaluated oral administration of the synthetic steroid 17α‐methyltestosterone (MT) to determine optimal dosage (30, 45, and 60 mg/kg of food) and days of feeding (30, 45, and 60) to attain efficient masculinization. The statistical analysis indicates a highly significant effect of both factors as well as for the interaction (P < 0.01). We registered significant differences in growth at the end of the experiment; fish fed with 60 mg of MT for 60 d reached the largest size, while fish fed with no MT were smaller. No significant differences were observed for survival (P > 0.05), ranging from 55.7 to 75.3% in the treatments. We recommend the use of 60 mg/kg of MT for 30 d for achieving successful sex reversal. This study provides valuable information supporting the inclusion of new species in aquaculture, reducing time and costs associated with sex reversal previously proposed for the species.     

Arbovirus isolations from mosquitoes in South Slovakia.

In the years 1973 and 1975 mosquitoes and some other Diptera (Tabanidae, Simuliidae, Hippoboscidae) were tested for virus. 13,924 mosquitoes, 75 horseflies and 60 blackflies were processed in 1973. Five strains of Tahyna virus were isolated from mosquito species Aedes vexans. 3,378 mosquitoes and 12 sheep keds were tested for virus in 1975. Twelve strains of Calovo virus were isolated from Anopheles maculipennis and one strain of Tahyna virus was obtained from Aedes vexans mosquitoes.     

Breeding objectives of Brangus cattle in Brazil

Our goal was to define a breeding objective for Brangus beef cattle in Brazil. Bioeconomic models were produced and used to estimate economic values (EVs). The scenarios simulated were typical full-cycle beef production systems that are used in tropical and subtropical regions. The breeding objective contained pregnancy rate (PR), warm carcass weight (WCW), mature cow weight (MCW), number of nematode eggs per gram of faeces (EPG) and tick count (TICK). Two models were used in series to estimate the EV. A deterministic model was used to simulate effects of PR, WCW and MCW on profitability with a constant parasite load. Subsequently, stochastic models were used to estimate economic values for TICK and EPG as consequences of their environmental effects on weight gains, mortality and health costs. The EV of PR, WCW, MCW, EPG and TICK, was US$1.59, US$2.11, −US$0.24, −US$5.35 and −US$20.88, respectively. Results indicate positive emphasis should be placed on PR (12.49%) and WCW (65.07%) with negative emphasis on MCW (13.92%), EPG (2.77%) and TICK (5.75%). In comparison with the indexes usually used, these results suggest a reformulation in the selection indexes of the beef production system in tropical and subtropical regions in order to obtain greater profitability.     

True hermaphroditism in a horned goat with 60XX/60XY chimerism

Anatomical, behavioral, histological, endocrinological, and cytogenetic characteristics were determined in a horned intersex goat. Histology of the gonads confirmed that the goat was a true hermaphrodite. Cytogenetic analysis showed that it was a chimera (60XX/60XY). Use of laparoscopy allowed determination of characteristics of the internal gonads.     

Two Hungarian isolates of cucumber mosaic virus from sweet pepper (Capsicum annuum) and melon (Cucumis melo): Identification and antiserum preparation

Two Hungarian virus isolates from sweet pepper (K8) and melon (S4) were identified as cucumber mosaic virus (CMV) on the basis of host plant reactions and serology. The isolates were purified and antisera prepared. Homologous antiserum titers in double-diffusion tests were 256 (K8) and 512 (S4). They were serologically closely related to each other and to other CMV isolates. On the basis of symptoms they belong to different symptomatological groups of CMV; this was supported by serological properties. Sedimentation coefficients were c. 93 S, at 2 mg ml^–1. Purified preparations, stained with 2% uranyl acetate, showed spherical particles. In ELISA purified preparations reacted with each other's antisera.Samenvatting Twee hongaarse virusisolaten uit paprika (K8) en meloen (S4) werden geïdentificeerd als komkommermozaïekvirus (CMV) met behulp van toetsplanten en serologie. Beide isolaten werden gezuiverd en er werden antisera tegen bereid. De homologe titers van de antisera in de agar-geldiffusietoets bedroegen 256 (K8) en 512 (S4). K8 en S4 waren serologisch nauw verwant aan elkaar, evenals aan andere CMV-isolaten. Op grond van hun symptomen op toetsplanten behoren ze tot verschillende symptomatologische groepen van CMV. Dit laatste werd gesteund door de serologische eigenschappen. Beide isolaten hebben een sedimentatiecoëfficiënt van ca 93 S, bij een concentratie van 2 mg ml^–1. Gezuiverde preparaten, gekleurd met 2% uranylacetaat, bleken bolvormige deeltjes te bevatten. In ELISA reageerden gezuiverde preparaten van K8 en S4 met elkaars antisera.     

Evidence of low levels of genetic diversity for the Phytophthora austrocedrae population in Patagonia,Argentina

Phytophthora austrocedrae is a recently discovered pathogen that causes severe mortality of Austrocedrus chilensis in Patagonia. The high level of susceptibility of the host tree, together with the distribution pattern of the pathogen, have led to the hypothesis that P. austrocedrae was introduced into Argentina. The aim of this study was to assess the population structure of P. austrocedrae isolates from Argentina in order to gain an understanding of the origin and spread of the pathogen. Genetic diversity was determined based on amplified fragment length polymorphisms (AFLPs). In total, 48 isolates of P. austrocedrae were obtained from infected A. chilensis trees, representing the geographical range of the host. Four primer combinations were used for the AFLP analysis. Of the 332 scored bands, 12% were polymorphic. Gene diversity (h) ranged from 0·01 to 0·03; the Shannon index (I) ranged from 0·01 to 0·04. A high degree of genetic similarity was observed among the isolates (pairwise S values = 0·958–1; 0·993 ± 0·009, mean ± SD). A frequency histogram showed that most of the isolate pairs were identical. Principal coordinate analysis using three‐dimensional plots did not group any of the isolates based on their geographical origin. The low genetic diversity (within and between sites) and absence of population structure linked to geographic origin, together with the aggressiveness of the pathogen and the disease progression pattern, suggest that P. austrocedrae might have been introduced into Argentina.     

First results of embryonic development,spawning and larval rearing of the Mediterranean spider crab Maja squinado (Herbst ) under laboratory conditions,a candidate species for a restocking program

The Mediterranean spider crab, Maja squinado, is depleted due to overfishing. The crab has virtually disappeared from areas where it was abundant, such as the Balearic Islands and the Catalan coast. Maja squinado, is economically and ecologically very valuable, and it is essential to obtain information on its biology and rearing conditions to attempt to repopulate the damaged stocks of the species in the Mediterranean basin. Herein, we describe the first successful rearing of M. squinado under laboratory conditions. Our results show that M. squinado is an excellent candidate for restocking using cultured juveniles. Two consecutive broods with a 1–4 day interbrood period were observed in the laboratory in wild‐caught females, the maximum observed duration of embryonic development of the egg mass being 32 days at 18.4 ± 0.9°C, and went through four different stages. The complete larval and first juvenile development was studied in laboratory cultures fed enriched Artemia metanauplius. At 19.6 ± 0.6°C, development from hatching to first crab moult took 17 days, and it comprised two zoeae stages and one megalopa stage. The survival rate at the different stages was monitored, and 7.13 ± 2.3% was achieved at the first crab instar.