Comparison of a flow assay for brucellosis antibodies with the reference cELISA test in West African Bos indicus.

Brucellosis is considered by the Food and Agricultural Organisation and the World Health Organisation as one of the most widespread zoonoses in the world. It is a major veterinary public health challenge as animals are almost exclusively the source of infection for people. It is often undiagnosed in both human patients and the animal sources and it is widely acknowledged that the epidemiology of brucellosis in humans and animals is poorly understood, particularly in sub-Saharan Africa.

Rabies control in rural Africa: evaluating strategies for effective domestic dog vaccination.

Effective vaccination campaigns need to reach a sufficient percentage of the population to eliminate disease and prevent future outbreaks, which for rabies is predicted to be 70%, at a cost that is economically and logistically sustainable. Domestic dog rabies has been increasing across most of sub-Saharan Africa indicating that dog vaccination programmes to date have been inadequate. We compare the effectiveness of a variety of dog vaccination strategies in terms of their cost and coverage in different community settings in rural Tanzania.

Exploring reservoir dynamics: a case study of rabies in the Serengeti ecosystem.

Knowledge of infection reservoir dynamics is critical for effective disease control, but identifying reservoirs of multi-host pathogens is challenging. Here, we synthesize several lines of evidence to investigate rabies reservoirs in complex carnivore communities of the Serengeti ecological region in northwest Tanzania, where the disease has been confirmed in 12 carnivore species.Long-term monitoring data suggest that rabies persists in high-density domestic dog Canis familiaris populations (> 11 dogs km(-2)) and occurs less frequently in lower-density (< 5 dogs km(-2)) populations and only sporadically in wild carnivores.

Farmer estimation of live bodyweight of cattle: implications for veterinary drug dosing in East Africa.

The ability of smallholder farmers and animal health workers to estimate live bodyweight can critically affect the likelihood of under- or over-dosing of veterinary compounds in decentralised systems where farmers administer a significant proportion of the veterinary treatments. A survey of 324 cattle owned by 170 farmers was conducted in Busia District, Kenya. Cattle were weighed on a standard calibrated scale and owners were asked to estimate the live weight of their animals.

Health management of horses under high challenge from trypanosomes: a case study from Serengeti, Tanzania.

Horses kept for recreational riding purposes by a wildlife tourism company in a heavily tsetse fly-infested region of north-western Tanzania were systematically monitored to investigate the occurrence, presentation and management of tsetse-transmitted trypanosomosis. During a 23-month period, 18 clinical cases were diagnosed (Trypanosoma brucei or Trypanosoma congolense were identified) and treated and trypanosomes were implicated of involvement in four deaths. Pyrexia consistently aided early detection (17 cases).

Serological survey for foot-and-mouth disease virus in wildlife in eastern Africa and estimation of test parameters of a nonstructural protein enzyme-linked immunosorbent assay for buffalo.

In this study we estimate the seroprevalence of foot-and-mouth disease virus (FMDV) in wildlife from eastern and central Africa. Sera were sourced from between 1994 and 2002 from a rinderpest surveillance program. Our study compared a nonstructural protein enzyme-linked immunosorbent assay (Cedi test) with a virus neutralization test.

Quantitative assessment of the likelihood of the introduction of classical swine fever virus into the Danish swine population.

Classical swine fever virus (CSFV) is a major infectious-disease agent of livestock and causes production losses through increased morbidity and mortality, particularly of young pigs. We identified the pathways for introduction of CSFV into Denmark and assessed the annual probability of introduction (based on a US Department of Agriculture model). We developed pathways based on material from scientific articles, reports from veterinary agencies and custom officers, and consultations with experts in the field.

Overviews of pathogen emergence: which pathogens emerge, when and why?

An emerging pathogen has been defined as the causative agent of an infectious disease whose incidence is increasing following its appearance in a new host population or whose incidence is increasing in an existing population as a result of long-term changes in its underlying epidemiology (Woolhouse and Dye 2001). Although we appear to be in a period where novel diseases are appearing and old diseases are spreading at an unprecedented rate, disease emergence per se is not a new phenomenon. It is almost certain that disease emergence is a routine event in the evolutionary ecology of pathogens, and part of a ubiquitous response of pathogen populations to shifting arrays of host species.

Delivery of health and husbandry improvements to working animals in Africa.

Problems have been identified in the delivery of extension messages about the maintenance of healthy and well-fed working animals. The different factors that need to be considered in developing effective disease control and prevention programmes for working oxen and equids including vector-borne diseases, helminth disease, and vaccination programmes have been reported and discussed and experiences in improving husbandry including footcare, harness, and worm management reported. Most draught animals are owned by people who lack the financial means to pay for or to access the information needed on nutritional supplements, vaccinations and drug treatment.

Tick cell lines: tools for tick and tick-borne disease research.

Over 40 cell lines are currently available from 13 ixodid and one argasid tick species. The successful isolation and propagation of several economically important tick-borne pathogens in tick cell lines has created a useful model to study interactions between tick cells and these viral and bacterial disease agents. Tick cell lines have already proved to be a useful tool in helping to define the complex nature of the host-vector-pathogen relationship.

Influence of host immunity on parasite diversity in Theileria parva.

We examined the influence of host immunity on the genotypic diversity of the intracellular transforming cattle parasite Theileria parva. By tracking the emergence of discrete parasite genotypes in an animal challenged with a bulk stabilate following immunization with its major component clone, we observed a profound modulation of genotypic frequencies in the breakthrough schizont population. In particular, no incidences of the immunizing clone were observed and a progressive decline was apparent in the relatedness of breakthrough genotypes to it.

Molecular epidemiology identifies only a single rabies virus variant circulating in complex carnivore communities of the Serengeti.

Understanding the transmission dynamics of generalist pathogens that infect multiple host species is essential for their effective control. Only by identifying those host populations that are critical to the permanent maintenance of the pathogen, as opposed to populations in which outbreaks are the result of 'spillover' infections, can control measures be appropriately directed. Rabies virus is capable of infecting a wide range of host species, but in many ecosystems, particular variants circulate among only a limited range of potential host populations.

The conservation relevance of epidemiological research into carnivore viral diseases in the serengeti.

Recent outbreaks of rabies and canine distemper in wildlife populations of the Serengeti show that infectious disease constitutes a significant cause of mortality that can result in regional extirpation of endangered species even within large, well-protected areas. Nevertheless, effective management of an infectious disease depends critically on understanding the epidemiological dynamics of the causative pathogen. Pathogens with short infection cycles cannot persist in small populations in the absence of a more permanent reservoir of infection.

African trypanosomiasis.

Trypanosomiasis remains one of the most serious constraints to economic development in sub-Saharan Africa and, as a consequence, related research has been subject to strong social and political as well as scientific influences. The epidemics of sleeping sickness that occurred at the turn of the 20th Century focussed research efforts on what became known as 'the colonial disease'. This focus is thought to have produced 'vertical' health services aimed at this one disease, while neglecting other important health issues.

Competitive suppression in mixed-clone parasite cultures.

Mixed-genotype infections occur frequently in natural populations. Parasite genotypes are expected to interact within a host: competing for shared nutrients and being affected by the host's immune response to each other. Theoretically, competing parasites can be expected to exhibit increased rates of replication.

Evaluation of three 3ABC ELISAs for foot-and-mouth disease non-structural antibodies using latent class analysis.

Background: Foot-and-mouth disease (FMD) is a highly contagious viral disease of even-toed ungulates. Serological diagnosis/surveillance of FMD presents several problems as there are seven serotypes worldwide and in the event of vaccination it may be necessary to be able to identify FMD infected/exposed animals irrespective of their vaccination status. The recent development of non-structural 3ABC protein (NSP) ELISA tests has greatly advanced sero-diagnosis/surveillance as these tests detect exposure to live virus for any of the seven serotypes of FMD, even in vaccinated populations.

Patterns in parasite epidemiology: the peak shift.

A characteristic relationship between infection and host age, with levels of infection reaching a peak in particular age classes, has been reported for many parasites. However, several field studies have shown that this relationship is not invariant: if age-infection data are compared across host populations, the peak level of infection is higher and occurs at a younger age when the transmission rate is high, and is lower and occurs at an older age when it is low. This pattern is called the ;peak shift'.

Cloned Theileria parva produces lesser infections in ticks compared to uncloned T. parva despite similar infections in cattle.

Experimental transmissions of cloned Theileria parva in cattle with Rhipicephalus appendiculatus ticks were compared to transmissions with uncloned T. parva during studies on the potential for genetic recombination during syngamy of Theileria to produce antigenic diversity for evasion of bovine immunity. Prevalence and abundance of T.

Canine vaccination--providing broader benefits for disease control.

This paper reviews the broader benefits of canine vaccination to human and animal health and welfare with an emphasis on the impacts of mass dog vaccination against rabies in countries of the less-developed world. Domestic dogs are the source of infection for the vast majority (>95%) of cases of human rabies worldwide, and dogs remain the principal reservoir throughout Africa and Asia. Canine vaccination against rabies has been shown to dramatically reduce the number of cases in dogs, the incidence of human animal-bite injuries (and hence the demand for costly post-exposure prophylaxis) and the likely number of human cases, primarily in children.

Animal movements and the spread of infectious diseases.

Domestic and wild animal population movements are important in the spread of disease. There are many recent examples of disease spread that have occurred as a result of intentional movements of livestock or wildlife. Understanding the volume of these movements and the risks associated with them is fundamental in elucidating the epidemiology of these diseases, some of which might entail zoonotic risks.

Epidemiology of porcine non-specific colitis on Scottish farms.

The objective of this study was to investigate epidemiological risk factors for porcine non-specific colitis (NSC). Forty-seven Scottish pig farms, with and without a clinical history of diarrhoea during the growing period (15-40 kg), were selected. The study included farm visits, clinical inspection of pigs, completion of farm management questionnaires, pathological tests into the cause of the diarrhoea and analysis of the non-starch polysaccharide (NSP) content of feeds.

A comparison of the effect of forage type and level of feeding on the digestibility and gastrointestinal mean retention time of dry forages given to cattle, sheep, ponies and donkeys.

Four cattle, sheep, ponies and donkeys were fed dehydrated lucerne, early-cut hay, later-cut hay or barley straw in a Latin square-based design for four periods of 35 d. In the first sub-period animals were fed the diets ad libitum (1-21 d) and in the second sub-period they were fed the same diet restricted to 0.75 of ad libitum intake (days 22-35).

Super-shedding cattle and the transmission dynamics of Escherichia coli O157.

The prevalence of Escherichia coli O157 displays striking variability across the Scottish cattle population. On 78% of farms, in a cross-sectional survey of 952, no shedding of E. coli O157 was detected, but on a small proportion, approximately 2%, very high prevalences of infection were found (with 90-100% of pats sampled being positive).

Prevalence and virulence factors of Escherichia coli serogroups O26, O103, O111, and O145 shed by cattle in Scotland.

A national survey was conducted to determine the prevalence of Escherichia coli O26, O103, O111, and O145 in feces of Scottish cattle. In total, 6,086 fecal pats from 338 farms were tested. The weighted mean percentages of farms on which shedding was detected were 23% for E.

Central point sampling from cattle in livestock markets in areas of human sleeping sickness.

We present the results of a study to determine the value of central point sampling in cattle markets as a means of estimating the trypanosomiasis (T. brucei s.l.