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Topic:Infectious Disease
Infectious diseases in horses encompass a range of illnesses caused by bacteria, viruses, fungi, or parasites. These diseases can affect various systems within the equine body, leading to symptoms that range from mild discomfort to severe systemic illness. Common infectious diseases in horses include equine influenza, strangles, equine herpesvirus, and West Nile virus. These diseases can be transmitted through direct contact with infected animals, contaminated surfaces, or vectors such as insects. Understanding the mechanisms of transmission, pathogenesis, and immune response is essential for effective prevention and control. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, diagnosis, treatment, and management of infectious diseases in horses.
Death of a horse infected experimentally with Anaplasma phagocytophilum. A 19-year-old horse that was one of a group of six horses infected experimentally with Anaplasma phagocytophilum for a study of the pathogenesis of equine granulocytic ehrlichiosis died suddenly two days after first showing clinical signs of disease. The clinical signs and laboratory findings observed before its death were similar to all those of the other infected horses, and to previous reports of this disease. A postmortem examination revealed widespread haemorrhaging in its internal organs, and vasculitis and thrombosis in the kidneys. These changes are consistent with disseminated intrava...
West Nile virus in Europe and Africa: still minor pathogen, or potential threat to public health? Until 1999 the West Nile virus had been reported only in the "Old world" and particularly in Europe, Africa, Middle East and Asia where it was responsible only for sporadic or size-and-time-limited outbreaks in humans and equines. The sudden and unexpected emergence of WN in New York in 1999, followed by a rapid and huge extension to the whole North America in less than four years, made health authorities aware of the potential of previously forgotten viruses to become a threat to public health. The present review will focus on the epidemiology of West Nile virus in Europe and Africa during th...
Live-attenuated recombinant equine herpesvirus type 1 (EHV-1) induces a neutralizing antibody response against West Nile virus (WNV). The immunogenicity in horses of a recombinant equine herpesvirus type 1 (EHV-1) vaccine expressing West Nile virus (WNV) prM and E proteins was studied. To construct the recombinant EHV-1, two-step en passant mutagenesis was employed for manipulation of a bacterial artificial chromosome (BAC) of vaccine strain RacH. Recombinant EHV-1 stably expressed the WNV prM and E proteins as demonstrated by indirect immunofluorescence and Western blotting. In addition, growth properties in vitro of the EHV-1/WNV recombinant were found to not be significantly different from those of the parental virus. To ...
Vaccination of horses against strangles using recombinant antigens from Streptococcus equi. Strangles is an upper respiratory tract infection in horses, which is highly contagious and one of the more costly diseases of the horse. Three recombinant antigens were used to vaccinate horses, which were then experimentally challenged with Streptococcus equi, the causative agent for strangles. The vaccinated horses showed significantly reduced bacterial growth (p=0.02) and nasal discharge (p=0.0004), a typical symptom of strangles. Other clinical signs of strangles were also reduced and at post mortem examination, lower rate of empyaema or scarring of the guttural pouches was found in the v...
Bacteraemia in neonatal foals: clinicopathological differences between Gram-positive and Gram-negative infections, and single organism and mixed infections. Treatment for bacteraemia in foals must be started before the identity of the causative organism is known. Information aiding selection of effective antimicrobials should improve outcome. Objective: To describe differences in clinical and clinicopathological data and outcome in foals with bacteraemia due to different classes of bacteria. Methods: Records of foals with a positive blood culture, age < 10 days and presenting to a university hospital 1995-2004, were reviewed. Bacterial culture results, subject details, historical information, physical examination findings at admission and clini...
Toxin production by and adhesive properties of Clostridium difficile isolated from humans and horses with antibiotic-associated diarrhea. Clostridium difficile is a common nosocomial pathogen in humans and animals that causes diarrhea and colitis following antibiotic therapy. Isolates of C. difficile obtained from faecal material from 20 human patients and 6 equine subjects with antibiotic-associated diarrhea were investigated regarding production of toxins A and B, their capacity to adhere to the human intestinal Caco-2 cell line and equine intestinal cells, and for the presence of fimbriae. The results showed that most (17/20) of the human clinical isolates produced both toxins A and B. One of the human isolates proved toxin A...
Standardization and validation of an agar gel immunodiffusion test for the diagnosis of equine infectious anemia using a recombinant p26 antigen. We developed and validated an agar gel immunodiffusion test (AGID) test for the diagnosis of equine infectious anemia (EIA) using as antigen the p26 protein of equine infectious anemia virus (EIAV) produced in the Escherichia coli expression system. The developed rp26-AGID test showed an excellent diagnostic relative sensitivity (100%) and specificity (100%) compared to a commercial AGID assay when 1855 field serum samples were analyzed. In addition, the rp26-AGID demonstrated to be a precise assay with excellent repeatability and reproducibility. In the analytical sensitivity trial, positive ...
Experiences with new generation vaccines against equine viral arteritis, West Nile disease and African horse sickness. Viral diseases constitute an ever growing threat to the horse industry worldwide because of the rapid movement of large numbers of horses for competition and breeding. A number of different types of vaccines are available for protective immunization of horses against viral diseases. Traditional inactivated and live-attenuated (modified live virus, MLV) virus vaccines remain popular and efficacious but recombinant vaccines are increasingly being developed and used, in part because of the perceived deficiencies of some existing products. New generation vaccines include MLVs with deletions and/or...
Survey of the large-animal diplomates of the American College of Veterinary Internal Medicine regarding knowledge and clinical use of polymerase chain reaction: implications for veterinary education. A questionnaire was developed to document the knowledge base of large-animal diplomates of the American College of Veterinary Internal Medicine (ACVIM) regarding polymerase chain reaction (PCR) technology and to identify the common use of this technology in equine practice. Ninety-three of the 278 mailed questionnaires were returned, for an overall response rate of 33.4%. Ninety respondents (99%) reported being familiar with the general principles of nucleic acid probe technology; however, only 52 (57%) knew the difference between conventional (traditional) and real-time (second-generation) PC...
In vitro susceptibility of six isolates of equine herpesvirus 1 to acyclovir, ganciclovir, cidofovir, adefovir, PMEDAP and foscarnet. Equine herpesvirus 1 (EHV-1) is an important equine pathogen that causes respiratory disease, abortion, neonatal death and paralysis. Although vaccines are available, they are not fully protective and outbreaks of disease may occur in vaccinated herds. Therefore, there is an urgent need for effective antiviral treatment. For three abortigenic (94P247, 97P70 and 99P96) and three neuropathogenic isolates (97P82, 99P136 and 03P37), the effect of acyclovir, ganciclovir, cidofovir, adefovir, 9-(2-phosphonylmethoxyethyl)-2,6-diaminopurine (PMEDAP) and foscarnet on plaque number was studied. Addition...
Evaluation of a real-time polymerase chain reaction assay for rapid identification of methicillin-resistant Staphylococcus aureus directly from nasal swabs in horses. Screening for nasal colonization is an important aspect of many methicillin-resistant Staphylococcus aureus (MRSA) control programs. Real-time polymerase chain reaction (RT-PCR) is an attractive alternative to standard culture techniques because of the considerably shorter turnaround time. An assay has been validated for diagnostic purposes in humans, however this methodology has not been evaluated in horses. The purpose of this study was to compare an RT-PCR assay for rapid identification of MRSA directly from nasal swabs in horses to standard culture techniques. Nasal swabs collected from 29...
Comparative evaluation of the sensitivity of LAMP, PCR and in vitro culture methods for the diagnosis of equine piroplasmosis. The sensitivity of LAMP, PCR and in vitro culture methods for the detection of Theileria equi and Babesia caballi was evaluated using tenfold serially diluted culture parasites. On day 1 post-culture, both T. equi and B. caballi parasites could only be observed at 1% parasite dilution from the in vitro culture method, whereas LAMP could detect up to 1 x 10(-3)% of both T. equi and B. caballi parasite dilutions, whilst PCR could detect 1 x 10(-3)% T. equi and 1 x 10(-1)% B. caballi parasite dilutions. On day 7 post-culture, the detection limit for T. equi and B. caballi in the in vitro culture ...
[Veterinarians–notables of the cities and the country. Some stages in their social ascent from the second half of the 18th century to the start of the 20th century]. During the second half of the 18th century scientific veterinary medicine, a new profession was born as a result of economic and military needs--losses of cattle as a consequence of infectious diseases and the growing demand for treatment to be given to the horses of the armies. At first the members of the emerging occupation, who are generally of very modest origin, hardly differ from the traditional actors of animal health. At the beginning of the 19th century the governments employ a large number of veterinarians for official missions to combat infectious diseases. As from the second half o...
Chlamydophila pneumoniae in horses: a seroepidemiological survey in Italy. We tested 731 sera from apparently healthy light horses against Chlamydophila pneumoniae, by a microimmuno-fluorescence (MIF) test. To verify cross-reactions with other species of chlamvdiae, all sera with an antibody titre > or = 32 to C. pneumoniae were tested against both C. psittaci and C. abortus. Antibodies to C. pneumoniae were detected in 194 out of 731 (26.5%) samples tested, with antibody titres ranging from 32 to 1024. No antibody titre > or = 32 was detected in sera to C. abortus. Only few sera with a high antibody titre to C. pneumoniae reacted weakly with C. psittaci at the dilut...
Evaluation of fecal samples from mares as a source of Rhodococcus equi for their foals by use of quantitative bacteriologic culture and colony immunoblot analyses. To determine whether mares are a clinically important source of Rhodococcus equi for their foals. Methods: 171 mares and 171 foals from a farm in Kentucky (evaluated during 2004 and 2005). Methods: At 4 time points (2 before and 2 after parturition), the total concentration of R equi and concentration of virulent R equi were determined in fecal specimens from mares by use of quantitative bacteriologic culture and a colony immunoblot technique, respectively. These concentrations for mares of foals that developed R equi-associated pneumonia and for mares with unaffected foals were compared. Data...
Morphometric analysis of the retina from horses infected with the Borna disease virus. Borna disease (BD) is a fatal disorder of horses, often characterized by blindness. Although degeneration of retinal neurons has been demonstrated in a rat model, there are controversial data concerning whether a similar degeneration occurs in the retina of infected horses. To investigate whether BD may cause degeneration of photoreceptors and possibly of other neuronal cells at least at later stages of the disease, we performed a detailed quantitative morphologic study of retinal tissue from Borna-diseased horses. BD was diagnosed by detection of pathognomonic Joest-Degen inclusion bodies in ...
In vitro cultivation of Plasmodium falciparum: studies with modified medium supplemented with ALBUMAX II and various animal sera. RPNI, a combination of three commercially available growth media (RPMI-1640, NCTC-135 and IMDM) has been found to support long term continuous cultivation of 3D7 strain of Plasmodium falciparum in the presence of 10% bovine calf serum. During the present study, the suitability of this medium was evaluated for the development of P. falciparum in the presence of horse, goat and rabbit sera as well as various concentrations of ALBUMAX II. RPNI medium supplemented with 10% bovine calf serum (RPNI-BCS) was used as control. The cultures were maintained in candle jars protocol and parasitaemia was mo...
Prevalence of Helicobacter equorum in faecal samples from horses and humans. Recently, a new enterohepatic Helicobacter species, H. equorum, was isolated from faecal samples of two clinically healthy horses. At the onset of this study, nothing was known about the prevalence of this organism in horses, nor was there any information available on the possible zoonotic character of this agent. This study aimed to determine the prevalence of H. equorum in faecal samples from equine and human origin. Therefore, faecal samples of 120 healthy privately owned horses, 227 healthy riding-school horses and 239 hospitalised horses were screened for H. equorum-DNA by means of a PCR ...
West Nile virus: recent trends in diagnosis and vaccine development. West Nile virus (WNV) is a mosquito-borne flavivirus, native to Africa, Europe, and Western Asia. In many respects, WNV is an outstanding example of a zoonotic pathogen that has leaped geographical barriers and can cause severe disease in human and horse. Before the emergence of WNV in the USA, only few methods of diagnosis were available. Recently, many changes in the fields of WN diagnosis and prevention have happened. This paper will review all these new tools. After a description of the main concerns in WNV and West Nile (WN) disease in humans and animals, this review will present the main...
Antigenic competition among different ‘O’ antigens of Salmonella enterica subspecies enterica serovars during hyperimmunization in pony mares. The present study on antigenic competition among somatic 'O' antigens of different Salmonella groups (A, B, C1, C2, D and E1) in mares revealed that the immune response to most of the antigens was not (A, B, C2) or little (C1, D) affected by antigenic competition. However, E1 group antigen, which induced high antibody titres (Avg. 12967.3) when given alone, produced almost 3.5 log2 lower antibody titres on giving with other antigens, indicating the antigenic competition among some Salmonella group antigens. The antigenic competition varied for different antigens even of the similar chemical na...
West Nile virus isolation from equines in Argentina, 2006. West Nile virus (WNV) was isolated from the brains of 3 horses that died from encephalitis in February 2006. The horses were from different farms in central Argentina and had not traveled outside the country. This is the first isolation of WNV in South America.
Rabies surveillance in the United States during 2005. During 2005, 49 states and Puerto Rico reported 6,417 cases of rabies in nonhuman animals and 1 case in a human being to the CDC, representing a 6.2% decrease from the 6,836 cases in nonhuman animals and 8 cases in human beings reported in 2004. Approximately 92% of the cases were in wildlife, and 8% were in domestic animals. Relative contributions by the major animal groups were as follows: 2,534 raccoons (39.5%), 1,478 skunks (23%), 1,408 bats (21.9%), 376 foxes (5.9%), 269 cats (4.2%), 93 cattle (1.5%), and 76 dogs (1.2%). Compared with numbers of reported cases in 2004, cases in 2005 decre...
Host cell tropism of equine herpesviruses: glycoprotein D of EHV-1 enables EHV-4 to infect a non-permissive cell line. Equine herpesviruses 1 and 4 (EHV-1 and EHV-4) cause equine respiratory disease worldwide. However, only EHV-1 is a cause of abortion and neurological disease, despite the two viruses having all 76 genes in common. In addition EHV-1 has a broader host range in cell culture than EHV-4, as exemplified by the rabbit kidney (RK) cell line that is permissive for EHV-1, but not for EHV-4. Here we describe that when EHV-4 produced in equine cells was inoculated onto RK cells expressing glycoprotein D of EHV-1 (RKgD1), infection developed as clusters of rounded cells, and this infectivity could be pas...
Comparative serological diagnosis of toxoplasmosis in horses using locally isolated Toxoplasma gondii. A total of 420 serum samples collected from horses of different ages, sexes and breeds, located at some horse farms in Egypt, were used for serological studies. A crude antigen of the locally isolated Toxoplasma gondii tachyzoites from horse tissues (LA) was used for the detection of T. gondii antibodies in horses. It showed good diagnostic efficiency (38.1%) by Enzyme Linked Immunosorbent Assay (ELISA). To increase this efficiency, an affinity purification process was performed. Two fractions were obtained from LA by CNBr-Sepharose 4B affinity column chromatography named; unbound (LAunb) and ...
[Occurrence and treatment of Bovicola (Damalinia) equi (Linnaeus, 1758) infestation on a thoroughbred horse farm.]. Lice infestations of horses occur mainly during winter months and are characterized by severe pruritus and an unkempt coat. Two lice have been described for equines namely Bovicola (Damalinia) equi and Haemotopinus asini. There is a scarcity of data on the occurrence and prevalence rates of these horse pathogens in Turkey. This paper reports a thoroughbred farm, in which two horses were found to be infested with B. equi. The horses were treated with propoxur and no lice or nymphs could be found after treatment for10 days.
Development and registration of recombinant veterinary vaccines. The example of the canarypox vector platform. The canarypox vaccine vector (ALVAC) technology has been used to develop and license several vaccines for companion animals and horses in the European Union and USA. ALVAC is a ubiquitous vector with high biosafety since it is non-replicative in mammalians, is genetically and physically stable, and able to induce both humoral and cell-mediated immune responses against the expressed transgene product. Specific rules apply for the development and registration of recombinant vector vaccines. The biology of the vector as well as the recombinant virus must be thoroughly documented to allow the risk...
