PubMed Health⌕ Search

Biomedical subjects

J E Madigan

Publications and source records attributed to J E Madigan.

At least 19 recordsLinked to original sources
PubMed2006

Initial clinical impressions of the U.C. Davis large animal lift and its use in recumbent equine patients.

The U.C. Davis Large Animal Lift (LAL) is a lightweight sling developed to help lift horses in clinical and rescue situations. Here we report on its first use in 16 recumbent horses with neurologic, muscular and musculoskeletal disorders. For each horse, history, sedation, ease and time of LAL application and hoisting, standing ability, LAL tolerance and outcome were recorded. The LAL was easily and safely applied in all horses in less than five minutes and the procedure was well tolerated with minimal to no sedation. While 10 horses were able to stand in the LAL after being hoisted, 6 horses were unable to stand and were eventually euthanized due to the inability to regain weight bearing function. The LAL has shown to be a useful devise to evaluate the standing ability of recumbent horses and can be used alone or in combination with the Anderson Sling Support Devise to allow standing support of horses with a variety of debilitating problems.

Animals↗
PubMed2003

Evidence for modulated immune response to Anaplasma phagocytophila sensu lato in cats with FIV-induced immunosuppression.

Human granulocytic ehrlichiosis (HGE) is an emerging infectious disease in which some patients experience unusual opportunistic infections. In this study, cats infected with the HGE agent, Anaplasma phagocytophila s.l., had clinical granulocytic ehrlichiosis (GE), anti-nuclear antibodies and increased IFN-gamma mRNA. In FIV-immunosuppressed cats with GE, there was upregulated IL-10 transcription but not IFN-gamma. Cats with FIV had poor response to vaccines, regardless of GE status. This preliminary report demonstrates that cats with FIV-infection make a good model of ehrlichiosis in an immunocompromised host, and that viral immunosuppression may not increase the severity of ehrlichiosis but may attenuate immune responses to the pathogen.

Anaplasma phagocytophilum↗
PubMed2003

Digenetic trematodes, Acanthatrium sp. and Lecithodendrium sp., as vectors of Neorickettsia risticii, the agent of Potomac horse fever.

Neorickettsia (formerly Ehrlichia) risticii, the agent of Potomac horse fever (PHF), has been recently detected in trematode stages found in the secretions of freshwater snails and in aquatic insects. Insectivores, such as bats and birds, may serve as the definitive host of the trematode vector. To determine the definitive helminth vector, five bats (Myotis yumanensis) and three swallows (Hirundo rustica, Tachycineta bicolor) were collected from a PHF endemic location in northern California. Bats and swallows were dissected and their major organs examined for trematodes and for N. risticii DNA using a nested polymerase chain reaction (PCR) assay. Adult digenetic trematodes, Acanthatrium sp. and/or Lecithodendrium sp., were recovered from the gastrointestinal tract of all bats and from one swallow. The intestine of three bats, the spleen of two bats and one swallow as well as the liver of one swallow tested PCR positive for N. risticii. From a total of seven pools of identical digenetic trematodes collected from single hosts, two pools of Acanthatrium sp. and one pool of Lecithodendrium sp. tested PCR positive. The results of this investigation provide preliminary evidence that at least two trematodes in the family Lecithodendriidae are vectors of N. risticii. The data also suggest that bats and swallows not only act as a host for trematodes but also as a possible natural reservoir for N. risticii.

Anaplasmataceae Infections↗
PubMed2002

Transmission of Anaplasma phagocytophila (human granulocytic ehrlichiosis agent) in horses using experimentally infected ticks (Ixodes scapularis).

Most human granulocytic ehrlichiosis (HGE) studies carried out in horses use needle inoculation of infected leucocytes or cell cultures. This route of inoculation does not accurately reflect natural infection of the tick-borne agent. To investigate whether tick transmission influences the course of granulocytic ehrlichiosis in the horse model, experimental transmission through infected laboratory-reared Ixodes scapularis ticks was attempted into two healthy horses. One additional horse served as negative control and was exposed to uninfected ticks. Eleven days after exposure to nymphal or adult ticks infected with Anaplasma phagocytophila (HGE agent) the two horses developed severe clinical and laboratory signs consistent with granulocytic ehrlichiosis. Bacteraemia was determined at various time points in the two horses by observation of morulae within neutrophils and by detection of A. phagocytophila genomic DNA by PCR of peripheral blood leucocytes. Further, both horses seroconverted. In contrast the control horse stayed uninfected. The results demonstrate that A. phagocytophila can be experimentally transmitted by infected nymphal and adult ticks and that the agent is able to produce a severe disease, similar to naturally occurring cases. Therefore, tick transmission is highly reproducible and can be successfully used in the equine animal model in order to study HGE.

Anaplasma phagocytophilum↗
PubMed2001

Suspected protozoal myeloencephalitis in a two-month-old colt.

A two-month-old Appaloosa colt developed neurological signs shortly after birth involving deficits affecting cranial nerves IV, VII, VIII, IX, X and XII, and possibly nerve VI. The most likely differential diagnoses were congenital anomalies, meningoencephalitides, trauma or nutritional causes. The foal was investigated by the analysis of cerebrospinal fluid (CSF), electromyelography (EMG), brain auditory evoked responses, magnetic resonance imaging (MRI), peripheral nerve biopsy, and Western blot analysis for the presence of intrathecal antibodies to Sarcocystis neurona, the causative agent of equine protozoal myeloencephalitis. Significantly abnormal EMG findings included spontaneous electrical activity of the tongue, suggesting denervation. The MRI was useful in ruling out masses, congenital anomalies and focal abscessation. The cytology of CSF revealed mild mononuclear reactivity. Western blot testing of CSF was positive, indicating the intrathecal presence of antibodies to S neurona. The foal was treated with pyrimethamine and trimethoprim-sulphadiazine for two months and returned to nearly normal neurologic status.

Animals↗
PubMed2001

Owner survey of headshaking in horses.

OBJECTIVE: To determine signalment, history, clinical signs, duration, seasonality, and response to various treatments reported by owners for headshaking in horses. DESIGN: Owner survey. ANIMALS: 109 horses with headshaking. PROCEDURE: Owners of affected horses completed a survey questionnaire. RESULTS: 78 affected horses were geldings, 29 were mares, and 2 were stallions. Mean age of onset was 9 years. Headshaking in 64 horses had a seasonal component, and for most horses, headshaking began in spring and ceased in late summer or fall. The most common clinical signs were shaking the head in a vertical plane, acting like an insect was flying up the nostril, snorting excessively, rubbing the muzzle on objects, having an anxious expression while headshaking, worsening of clinical signs with exposure to sunlight, and improvement of clinical signs at night. Treatment with antihistamines, nonsteroidal anti-inflammatory drugs, corticosteroids, antimicrobials, fly control, chiropractic, and acupuncture had limited success. Sixty-one horses had been treated with cyproheptadine; 43 had moderate to substantial improvement. CONCLUSIONS AND CLINICAL RELEVANCE: Headshaking may have many causes. A large subset of horses have similar clinical signs including shaking the head in a vertical plane, acting as if an insect were flying up the nostrils, and rubbing the muzzle on objects. Seasonality and worsening of clinical signs with exposure to light are also common features of this syndrome. Geldings and Thoroughbreds appear to be overrepresented. Cyproheptadine treatment was beneficial in more than two thirds of treated horses.

Animals↗
PubMed2001

Susceptibility of cattle to infection with Ehrlichia equi and the agent of human granulocytic ehrlichiosis.

OBJECTIVE: To determine susceptibility of cattle to infection with Ehrlichia equi and the agent of human granulocytic ehrlichiosis (HGE). DESIGN: Experimental disease and prevalence survey. ANIMALS: 6 cattle, 2 horses, and 2,725 serum samples from healthy cattle. PROCEDURE: 2 cattle and 1 horse were inoculated with E equi, 2 cattle and 1 horse were inoculated with the HGE agent, and 2 cattle served as sham-inoculated controls; inoculated animals were evaluated via clinical, hematologic, serologic, and real-time polymerase chain reaction tests. Prevalence of antibodies against E equi in 2,725 healthy cattle was determined by use of an indirect immunofluorescent technique. RESULTS: No abnormal clinical or hematologic findings or inclusion bodies within granulocytes were observed in the cattle after inoculation, and results of all polymerase chain reaction tests were negative. Seroconversion in inoculated cattle developed 10 to 12 days after inoculation (reciprocal titers, 160). Both horses developed clinical signs of ehrlichiosis. Five of 2,725 (0.18%) cattle were seropositive for E equi, with titers ranging from 20 to 80. All seropositive cattle originated from the same tick-rich region in the Sierra Nevada foothills. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that cattle are not susceptible to infection with E equi or the agent of HGE and that prevalence of exposure to E equi in healthy cattle is low. Therefore, E equi and the agent of HGE are likely of negligible importance for cattle in North America.

Animals↗
PubMed2001

Spatial distribution of seropositivity to the causative agent of granulocytic ehrlichiosis in dogs in California.

OBJECTIVE: To assess spatial and temporal patterns of seroprevalence among dogs in California to the causative agent of granulocytic ehrlichiosis (GE). SAMPLE POPULATION: Sera of 1,082 clinically normal dogs from 54 of 59 counties in California in 1997 to 1998. PROCEDURES: Serum-specific IgG reactivity to Ehrlichia equi was assessed by use of an immunofluorescent antibody assay, using E. equi-infected horse neutrophils as substrate. Data were analyzed, using a geographic information system. Spatial analysis of seroprevalence included first order Bayesian analysis of seroprevalence and second order analysis of clustering by K-function and Cuzick-Edwards tests. Monthly seroprevalence among dogs was examined by use of regression on monthly densities of Ixodes pacificus adults and nymphs. RESULTS: Seroprevalence among dogs to E. equi was 8.68%. Data were seasonally bimodal with highest prevalence in winter (when adult ticks were abundant) and a secondary peak in late spring (corresponding to nymphal ticks). Humboldt County had the highest seroprevalence (47.3%), and other northern coast range counties had seroprevalence from 15 to 30%. CONCLUSIONS AND CLINICAL RELEVANCE: The patchy distribution of exposure to Ehrlichia organisms is a subset of the distribution of the tick vector. This may reflect enzootic cycles or climatic or historical factors that limited the range of the disease. Dogs, horses, and humans from north coast range counties in California are at increased risk of GE. These data provide a background for assessing risk of infection in horses and dogs, depending on geographic location. Dogs may be sentinels for assessing risk of GE in humans.

Animals↗
PubMed2000

Molecular detection of an Ehrlichia-like agent in rainbow trout (Oncorhynchus mykiss) from Northern California.

Ehrlichia DNA was identified by nested PCR in rainbow trout (Oncorhynchus mykiss) collected from a creek in northern California where Potomac horse fever is endemic. Ehrlichia DNA was found in tissues from several organs including the gills, heart, spleen, liver, kidneys and intestine of trout and from three different adult digenetic trematodes (Deropegus sp., Crepidostomum sp., Creptotrema sp.) parasitizing the gallbladder and/or the intestine of the trout. Sequencing of PCR-amplified DNA from the 16S rRNA gene indicated that the source organism was most closely related to the sequences of E. risticii (level of sequence similarity 96.0%), the SF agent (95.9%), E. sennetsu (95.8%), and Neorickettsia helminthoeca (95.3%). The data suggest that trout and parasitic trematodes may be involved in the epidemiology of an Ehrlichia-like agent belonging to the E. sennetsu genogroup. Whether the fish agent infects horses, dogs, or human beings, and whether it causes disease, remain to be determined.

Animals↗
PubMed2000

Infection rate of Ehrlichia risticii, the agent of Potomac horse fever, in freshwater stream snails (Juga yrekaensis) from northern California.

Juga yrekaensis freshwater snails were tested for trematode stages and for Ehrlichia risticii DNA using a nested PCR assay. Snails were collected monthly from two Potomac horse fever (PHF) endemic locations in northern California (Montague and Weed). The trematode infection rate varied between 40 and 93.3% in large snails (shell size >15mm) and between 0 and 13.3% in small snails (<15mm). The highest trematode infection rate for large and small snails was recorded in September and the lowest infection rate for large snails was recorded in June (Weed) and October (Montague). The E. risticii PCR infection rate among small snails from both sites was similar and varied monthly between 0 and 3.3%. The PCR infection rate for large snails from Weed was high in May (20.0%) and decreased progressively until November (10.0%). The PCR infection rate for large snails from Montague was 5.0% in May, 26.3% in August and 16. 7% in October. PCR-positive snails were always related to the microscopic detection of trematode stages (virgulate cercariae). This study provides evidence that J. yrekaensis are infected with trematode cercariae that harbor E. risticii. The number of snails harboring trematode stages and the number of PCR positive snails varied with the size of the snails, the month of collection, and the geographic origin.

Animals↗
PubMed2000

Detection and quantitation of Ehrlichia risticii genomic DNA in infected horses and snails by real-time PCR.

A real-time quantitative PCR using the TaqMan fluorogenic detection system (TaqMan PCR) was established for identification of Ehrlichia risticii, the agent of Potomac horse fever (PHF). The TaqMan PCR identified an 85 base pair section of the 16S rRNA gene by use of a specific fluorogenic probe and two primers. This technique was specific for eight tested E. risticii strains. The TaqMan system identified 10 copies of a cloned section of the 16S rRNA gene of E. risticii. The sensitivity and specificity of the TaqMan PCR were similar to those of conventional nested PCR. The TaqMan PCR was evaluated on horses with infectious colitis and on freshwater stream snails collected from regions with a history of PHF. E. risticii could be detected in 22 of 153 (14.4%) horses with infectious colitis and in 25 of 234 (10.7%) snails in the TaqMan PCR. The same results were obtained in the conventional nested PCR. The Ehrlichia-load was in the range of 10,000-9,000,000 and 35,000-680, 000,000 Ehrlichia equivalents per microg leukocyte DNA and snail DNA, respectively.

Animals↗
PubMed2000

Ehrlichial diseases.

Equine granulocytic and monocytic ehrlichiosis caused by Ehrlichia equi and E. risticii, respectively, are seasonal diseases in horses that occur throughout the United States E. equi is transmitted by lxodes ticks and causes high fever, depression, anorexia, limb edema, petechiation, icterus, ataxia, and stiffness in gait. E. risticii, also known as the agent of Potomac horse fever, causes a febrile illness with a colitis of variable severity. Its occurrence is associated with aquatic habitats. The natural route of transmission is oral, through the ingestion of E. risticii infected trematode stages either free in water or in an intermediate host, such as aquatic animals.

Animals↗
PubMed2000

ankA: an Ehrlichia phagocytophila group gene encoding a cytoplasmic protein antigen with ankyrin repeats.

Human granulocytic ehrlichiosis (HGE) is a potentially fatal, tick-borne disease caused by a bacterium related or identical to Ehrlichia phagocytophila. To identify and characterize E. phagocytophila group-specific protein antigen genes, we prepared and screened HGE agent and Ehrlichia equi genomic DNA expression libraries using polyclonal equine E. equi antibodies. Two clones, one each from HGE agent and E. equi, that were recognized specifically by antibodies to the E. phagocytophila group ehrlichiae had complete open reading frames of 3,693 and 3,615 nucleotides, respectively. The two clones were 96.6% identical and predicted a protein with at least 11 tandemly repeated ankyrin motifs. Thus, the gene was named ank (for ankyrin). When the encoded protein, named AnkA, was expressed in Escherichia coli, it was recognized by antibodies from rabbits and mice immunized with the HGE agent, sera from humans convalescent from HGE, and sera from horses convalescent from HGE and E. equi infection. Monospecific AnkA antibodies reacted with proteins in HGE agent immunoblots, and AnkA monoclonal antibodies detected cytoplasmic antigen in E. phagocytophila group bacteria and also detected antigen associated with chromatin in infected but not uninfected HL-60 cell cultures. These results suggest that this Ehrlichia protein may influence host cell gene expression.

Amino Acid Sequence↗
PubMed2000

Experimental inoculation with human granulocytic Ehrlichia agent derived from high- and low-passage cell culture in horses.

We report the successful infection throughout intravenous inoculation with low and high passage of in vitro-grown human granulocytic ehrlichiosis (HGE) agent in horses. Differences in disease severity but not in incubation time, hematological changes, PCR detection, ehrlichial load, seroconversion time, and titer range were noted between horses infected with a low and a high passage of in vitro-grown HGE agent.

Animals↗