Nomenclature for parasitic diseases: cohabitation with inconsistency for how long and why?

The author surveys the early history of nomenclature for parasitic diseases or infections which led to the existing usage of synonymous names with diverse spellings for denominating the same disease entities. In order to diminish heterogeneity in nomenclatural usage, principles of the standardized nomenclature of parasitic diseases (SNOPAD) have been put forward by the World Association for the Advancement of Veterinary Parasitology. Pros and cons regarding the SNOPAD concept are discussed in seeking consensus terminology. The need for a standard nomenclature may be judged differently. SNOPAD is just a guideline based on carefully reasoned and clearly defined principles for those authors and editors dissatisfied with the existing heterogeneous and inconsistent nomenclatural usage and wish to rely on a uniform and standard disease nomenclature. The major suggestion of SNOPAD is the use solely of suffix -osis when disease name is coined from the name of a parasite taxon. Meanwhile, the proposed principles were found sensible and accepted more in the field of veterinary, less in medical parasitology. In a recent survey it has been revealed that the majority (73.8%) of 126 national language parasitological textbooks or compendia from 21 countries of Europe published since 1990 adopted consistent '-osis' disease terminology and the rest (26.2%) used a mixture of disease names ending in '-osis' and '-iasis' inconsistently. For achieving substantial shift towards the use of more consistent disease terminology, the interest and support of the parasitologists' community is required. Editorials and database producers hold the key to further progress provided they see the advantages of the use of a single name of worldwide currency for each disease entity.     

Oral vaccines for finfish: academic theory or commercial reality?

Aquaculture is the fastest growing food-producing sector, providing an acceptable supplement to and substitute for wild fish and plants. Increased production intensification, particularly in high-value species, involves substantial stress, which, as in other captive livestock species, has resulted in outbreaks of major diseases and related mortalities. Widespread use of antibiotics has led to the development of antibiotic-resistant bacteria and the accumulation of antibiotics in the environment and the flesh of fish. Thus, recently effort has been dedicated to vaccine development. Vaccination in fish is complicated by their aquatic environment. Individual injections are labor-intensive and stressful, since fish have to be removed from the water and anaesthetized. Some vaccines offer a limited duration of protection, and thus booster applications are required. In salmonid species, many commercial vaccines use oil-based adjuvants, resulting in a greatly improved duration of protection. However, oil-based adjuvants have been related to significant growth depression, internal adhesions and injection site melanization, resulting in carcass downgrading. Oral administration to aquatic species is by far the most appealing method of vaccine delivery: there is no handling of the fish, which reduces stress; and administration is easy and suitable for mass immunization. However, few oral vaccines have been commercialized, due in part to the increased quantity of antigen required to provoke an immune response, and the lack of an adequate duration of protection. For effective oral delivery, protective antigens must avoid digestive hydrolysis and be taken up in the hindgut in order to induce an effective protective immune response. Antigen encapsulation technologies have been used to protect antigen; however, such strategies can be expensive and are not always effective. Alternative approaches, currently under development, are discussed.     

Selection against canine hip dysplasia: success or failure?

Canine hip dysplasia (CHD) is a multifactorial skeletal disorder which is very common in pedigree dogs and represents a huge concern for canine welfare. Control schemes based on selective breeding have been in operation for decades. The aim of these schemes is to reduce the impact of CHD on canine welfare by selecting for reduced radiographic evidence of CHD pathology as assessed by a variety of phenotypes. There is less information regarding the genotypic correlation between these phenotypes and the impact of CHD on canine welfare. Although the phenotypes chosen as the basis for these control schemes have displayed heritable phenotypic variation in many studies, success in achieving improvement in the phenotypes has been mixed. There is significant room for improvement in the current schemes through the use of estimated breeding values (EBVs), which can combine a dog's CHD phenotype with CHD phenotypes of relatives, other phenotypes as they are proven to be genetically correlated with CHD (especially elbow dysplasia phenotypes), and information from genetic tests for population-relevant DNA markers, as such tests become available. Additionally, breed clubs should be encouraged and assisted to formulate rational, evidenced-based breeding recommendations for CHD which suit their individual circumstances and dynamically to adjust the breeding recommendations based on continuous tracking of CHD genetic trends. These improvements can assist in safely and effectively reducing the impact of CHD on pedigree dog welfare.     

Efficacy of vaccines against bacterial diseases in swine: what can we expect?

This paper discusses what can be expected with regard to efficacy of antibacterial vaccines used in swine, based on the present knowledge of pathogen–host interactions. First, vaccination against bacteria that mainly cause disease by production of exotoxins is considered. Vaccines containing the inactivated toxin or a non-toxic but antigenic recombinant protein derived from the exotoxin can be expected to provide protection against disease. The degree of protection induced by such vaccines varies, however, depending amongst other things on the pathogenesis of the disease. Vaccination against clostridial infections, Actinobacillus pleuropneumoniae infections, progressive atrophic rhinitis and enterotoxigenic Escherichia coli, is considered. The second part of the article deals with vaccination against extracellular bacteria. Protection against these bacteria is generally mediated by antibodies against their surface antigens and certain secreted antigens, but cellular immunity may also play a role. Efficacy of vaccines against swine erysipelas, Streptococcus suis infections, Mycoplasma hyopneumoniae infections and swine dysentery is discussed. Finally, vaccination against facultatively intracellular bacteria is considered. For protection against these bacteria cell-mediated immunity plays an important role, but antibodies may also be involved. It is generally accepted that live-attenuated vaccines are more suitable for induction of cell-mediated immunity than inactivated vaccines, although this also depends on the adjuvant used in the vaccine. As an example, vaccination against Salmonella enterica serotype Typhimurium is discussed.     

Heck cattle in the Oostvaardersplassen: risk for infectious diseases or not?

This article discusses risk analysis of infectious diseases in a cattle population. Heck cattle living in nature reserve 'De Oostvaardersplassen' were studied as an example of the risk analysis approach. Twenty-five adult cattle were tested for every infectious disease agent that the risk analysis indicated might be prevalent. All sampled cattle tested positive for Bovine Herpesvirus 1, whereas the prevalence of antibodies against other infectious disease agents was below the level that was assumed to be the threshold for spread of the disease to cattle in the surrounding areas. Risk management of infectious diseases was expressed in a so-called 'low-risk profile'. The risk of introduction or spread of infectious diseases was estimated to be very low as long as the population was kept strictly enclosed.     

Organic pig farming: what about parasitic infections?

The parasitological problems that may arise in organic pig farming are discussed. The rearing of pigs outdoors increases substantially the chances that several parasite species will complete their life cycle. Moreover, zoonoses may play an important role. Parasite species that may cause problems are discussed, as are control measures, when possible.     

Calcium: total or ionized?

Measurement of serum total calcium (tCa) has been relied on for assessment of calcium status, despite the fact that it is the ionized calcium (iCa) fraction that has biologic activity. Serum tCa does not accurately predict iCa status in many clinical conditions. For accurate assessment of iCa status, iCa should be directly measured. Anaerobic measurement of serum iCa under controlled conditions provides the most reliable assessment of calcium status; aerobic measurement of iCa with species-specific pH correction is highly correlated with anaerobic measurements.     

Is AZT/3TC therapy effective against FIV infection or immunopathogenesis?

In vitro and in vivo prophylactic and therapeutic efficacy of AZT/3TC treatment was evaluated against feline immunodeficiency virus (FIV) infection. In vitro studies utilized FIV-infected peripheral blood mononuclear cells (PBMCs) or FIV-infected T-cell lines treated with AZT (azidothymidine) alone, 3TC alone, or AZT/3TC combination and tested for anti-FIV activity and drug toxicity. AZT/3TC combination had additive to synergistic anti-FIV activities in primary PBMC but not in chronically infected cell lines. In vivo studies consisted of four treatment groups (n=15) of SPF cats receiving AZT/3TC combination (5-75 mg/kg/drug PO BID for 8 or 11 weeks) and one control group (n=9) receiving oral placebo. Group I (n=6, 150 mg/kg/drug/day) was treated starting 3 days pre-FIV inoculation, whereas Group II (n=3, 150 mg/kg/drug/day) and Group III (n=3, 100 mg/kg/drug/day) treatments were simultaneous with FIV inoculation. Group IV treatment (n=3, 100 mg/kg/drug/day) was initiated 2 weeks post-FIV inoculation. All cats were monitored for drug toxicity and FIV infection. Eighty-three percent of cats in Group I and 33% of cats in Groups II and III were completely protected from FIV infection. A significant delay in infection and antibody seroconversion was observed in all unprotected cats from Groups I, II and III. Group IV cats had only a slight delay in FIV antibody seroconversion. Adverse drug reactions (anemia and neutropenia) were observed at high doses (100-150 mg/kg/drug/day) were reversible upon lowering the dose (20 mg/kg/drug/day). In contrast, AZT/3TC treatment had no anti-FIV activity in chronically infected cats. Furthermore, severe clinical symptoms caused by adverse drug reactions were observed in some of these cats. Overall, AZT/3TC treatment is effective for prophylaxis but not for therapeutic use in chronically FIV-infected cats.     

Canine leishmaniosis in the United Kingdom: A zoonotic disease waiting for a vector?

Leishmaniosis is an important sand fly transmitted protozoan disease of dogs and humans. In northern Europe, infection is mainly restricted to dogs that have travelled to and/or from endemic areas of the Mediterranean region during periods when there is high sand fly exposure, mostly between March and November. Infected dogs in these areas in northern latitudes are a potential reservoir should incursion of a competent vector occur. However, information on the scale of the potential reservoir in the UK is lacking. Confirmed cases of canine leishmaniosis entering the United Kingdom between 2005 and 2007 were identified using diagnostic samples submitted to the Department of Clinical Veterinary Science, University of Bristol and from collaborating laboratories (n = 257). All study dogs had clinico-pathological signs compatible with leishmaniosis, as typically reported in endemic countries and were leishmania positive in real time or conventional PCR tests, IFA serology and/or tissue microscopic examination for amastigote identification. Information obtained from each case included travel history, habitat, clinico-pathological findings and geographical location once located in the UK. The majority of dogs with complete travel history (n = 183) had spent at least 6 months in Spain (105/183), 28/183 were rescued from re-homing centres in the country of origin and 26/183 entered the UK with confirmed leishmaniosis. Once located in the UK, the majority of positive cases were resident in south and central England. The spectrum of clinico-pathological signs for this group of dogs is similar to that reported in endemic countries. These data confirm that a potentially significant reservoir of infected dogs is resident in areas where future climatic conditions may support introduction of competent vectors.     

Complex bacterial flora of imported pet tortoises deceased during quarantine: Another zoonotic threat?

Turtoises are a great puzzle when it comes to their bacterial flora, the composition and structure of which are still unknown in details. Its component which has been best described so far is Salmonella spp., presumably due to the threat of reptile-associated salmonellosis in humans. This investigation tried to assess and characterize intestinal bacterial flora of imported tortoises found dead during quarantine. Most of the animals carried various serovars of Salmonella showing no antimicrobial resistance. Presence of multiresistant Escherichia coli was possibly a result of industrial breeding and high usage of antimicrobials. Thirteen bacterial species or genera like Citrobacter spp., Morganella spp., Pseudomonas spp. were identified. Their commensal character is assumed, although pathogenic potential might be verified. The results indicate global tortoise trade as a source of common and exotic bacteria or antimicrobial resistance mechanisms in new geographical areas. These dangers indicate the need for a systematic survey of exotic pets and establishment of legal requirements for reptile health conditions on breeding, trade premises and in households with such pets.     

Inflammatory bowel diseases in horses: What do we know?

Chronic inflammatory bowel diseases (IBDs) are a group of gastrointestinal (GI) disorders described in both humans and animals, but unlike in other species, in horses they are poorly defined and there is a lack of standardisation of the method of diagnosis. Although there is an impellent need of consensus on the nomenclature, diagnostic work-up, diet, treatment and management of horses with a suspected IBD, the aim of this review is to give initial guidelines for practitioners dealing with suspected cases. It provides a summary of the most relevant literature on the topic and presents the current knowledge on the clinical signs, diagnostic work-up, treatment and prognosis of IBDs in horses.     

Mycoplasma host specificity: fact or fiction?

Bacteria of the genus Mycoplasma are the smallest organisms known to be capable of self-replication. They only occur in association with animal host cells on which they are dependant for many pre-formed nutrients since they lack many of the metabolic pathways associated with energy production and the synthesis of cell components found in other species of bacteria. It is generally thought that most species of Mycoplasma are very host specific but there are many reports of mycoplasmas in hosts that are not perceived as their normal habitat. Sometimes these "crossings" may have a pathological impact particularly where there may be predisposing conditions such as immunodeficiency. These are often reported in humans but may also occur in animals whose immune or physiological status is not known. This review brings together some of these reported incidents and speculates on their potential impact for laboratory diagnosis.