Rapid Diagnosis of Babesia gibsoni by Point-of-Need Testing by Insulated Isothermal PCR in Dogs at High Risk of Infection.

BACKGROUND: Dogs seized by law enforcement agencies during dogfighting investigations are at increased risk of Babesia gibsoni infection. A rapid and cost-effective diagnostic test would increase the feasibility of mass screening of dogs for infection and monitoring treatment efficacy in B. gibsoni-infected dogs. OBJECTIVE: To determine the performance of a point-of-need insulated isothermal PCR (iiPCR) test for diagnosis of B. gibsoni in dogs rescued in dogfighting investigations. ANIMALS: Two hundred and thirty-three dogs seized in dogfighting investigations. METHODS: Cross-sectional study. Whole blood samples were tested for B. gibsoni and Babesia spp. by iiPCR. Results were compared to a reference standard comprised of concordant results from real-time PCR in a commercial diagnostic laboratory and antibody titers. RESULTS: The iiPCR system was quick to learn, portable, and had a short processing time of <2 hours. Sensitivity and specificity of the iiPCR assay for B. gibsoni were 90% (95% confidence interval [CI] 81-95%) and 99% (CI, 95-100%), respectively. Sensitivity and specificity of the iiPCR assay for Babesia spp. were 87% (CI, 78-93%) and 98% (CI, 0.94-99%), respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: The iiPCR system produced few false-positive results, indicating that positive results are likely to represent true infections when used in high-risk animals. The iiPCR system can fail to identify 10-15% of truly infected dogs. However, the portability, speed, and economy of the iiPCR system compared to testing through a reference laboratory can allow rescue groups to screen and identify infection in more dogs.

Electrocardiographic findings in dogs with motor vehicle-related trauma.

Motor vehicle-related injury is the most common form of trauma incurred by dogs, and cardiac arrhythmias are a well-recognized complication. Although posttraumatic arrhythmias are often observed, little is known regarding their frequency. This study utilized continuous ambulatory electrocardiography (i.e., Holter monitoring) to describe the cardiac rhythm disturbances in 30 dogs sustaining trauma in motor vehicle accidents. Ventricular ectopy was identified by Holter monitoring in 29 of 30 dogs, although the initial electrocardiogram (EKG) only documented ventricular ectopic complexes (VECs) in four dogs. Ventricular ectopy was infrequent in most dogs (i.e., 62% of the dogs had less than 100 VECs per day for the entire study), but 16% developed frequent arrhythmias (greater than 4,000 VECs per day). In all cases, the VECs were observed within 24 hours of injury. Forty-three percent of dogs had at least one episode of ventricular tachycardia, including several dogs that had an overall infrequent rate of VECs (i.e., less than 100 or 100 to 1,000 VECs per day). Although baseline EKGs are useful in identifying arrhythmias in most dogs, the length of the recording should be increased to improve the likelihood of observing an abnormal EKG event. Most importantly, additional EKGs should be obtained or continuous EKG monitoring should be performed in dogs that display clinical signs that could be attributed to ventricular arrhythmias.

Calcium channel blockers in veterinary medicine.

Calcium channel blockers are becoming increasingly popular in veterinary medicine for the treatment of systemic hypertension, cardiac arrhythmias, and hypertrophic cardiomyopathy. Calcium is vital to many cellular functions and thus stringent regulation of intracellular calcium concentrations is required. Pharmacologic manipulation of the regulatory mechanisms has the potential to alter cellular function in all body systems. In human medicine, calcium channel blockers are being evaluated for, among other things, use in treating glaucoma, deep vein thrombosis, and pulmonary hypertension, in renal transplantation, and for prevention of reperfusion injury. The potentially beneficial effects of these drugs have often been overshadowed by adverse effects including hypotension, inappetence, bradycardia, conduction abnormalities, and decreased cardiac output. With the introduction of sustained-release formulations (diltiazem) and 2nd generation calcium channel blockers (amlodipine) many of these effects have been attenuated or eliminated. This paper will review the functions of calcium and the calcium channels as well as discussing the classes and current and potential uses of the various calcium channel blockers.

Fluid therapy in the cardiac patient.

Correcting fluid deficits and preventing fluid overload in patients with cardiac disease can be challenging. The purpose of the fluid therapy, the projected duration of the therapy, and the type of heart disease affecting the patient play important roles in the decision-making process. In addition, the distinction between patients who are not symptomatic (NYHA Class I) and those who are symptomatic (NYHA Classes II to IV) for their cardiac disease should be made early in fluid therapy planning.

Analysis of an SEIRS epidemic model with two delays.

A disease transmission model of SEIRS type with exponential demographic structure is formulated. All newborns are assumed susceptible, there is a natural death rate constant, and an excess death rate constant for infective individuals. Latent and immune periods are assumed to be constants, and the force of infection is assumed to be of the standard form, namely proportional to I(t)/N(t) where N(t) is the total (variable) population size and I(t) is the size of the infective population. The model consists of a set of integro-differential equations. Stability of the disease free proportion equilibrium, and existence, uniqueness, and stability of an endemic proportion equilibrium, are investigated. The stability results are stated in terms of a key threshold parameter. More detailed analyses are given for two cases, the SEIS model (with no immune period), and the SIRS model (with no latent period). Several threshold parameters quantify the two ways that the disease can be controlled, by forcing the number or the proportion of infectives to zero.

The population dynamics of two vertically transmitted infections.

The transmission of Keystone virus in the mosquito Aedes atlanticus and of Rickettsia rickettsii in the tick Dermacentor andersoni is modeled and analyzed. Both of these infections can be transmitted vertically from an infective parent to newborn offspring as well as horizontally via direct or indirect contacts with infected individuals. The vertical transmission mechanism plays a major role in the maintenance of these infections and its effects are analyzed in detail. This same mechanism can act as a means for controlling the size of the infected host population and an analysis of this effect is also provided. The sensitivity of the threshold parameters and the endemic prevalence rates of the disease to variations in the basic infection transmission components are investigated. The transmission components that are considered include the ability to transmit the pathogen vertically as well as horizontally, the size of the host population, and survival probabilities of the hosts.

Analysis of the complicated dynamics of some harvesting models.

In this paper we will study in a qualitative way discrete single species population models including harvesting. The class of models under consideration is quite general. In fact, we will study models with fixed parameter values. However, the obtained results do have implications for the models if one varies the parameters slightly. The models with so-called "Allee-effect", i.e. the population will die out whenever the size of the population is below some threshold, are included in the class of models we studied.

Analysis of a model of a vertically transmitted disease.

A model is presented of a disease that can be transmitted directly from parent to offspring (vertical transmission) as well as through contact with infectives. A global stability analysis is given for the basic model and the epidemiological effects of vertical transmission are discussed. The effects of the addition of maturation and incubation delays as well as spatial diffusion are analyzed in some special cases.

The effect of integral conditions in certain equations modelling epidemics and population growth.

Models of epidemics that lead to delay differential equations often have subsidiary integral conditions that are imposed by the interpretation of these models. The neglect of these conditions may lead to solutions that behave in a radically different manner from solutions restricted to obey them. Examples are given of such behavior, including cases where periodic solutions may occur off the natural set defined by these conditions but not on it. A complete stability analysis is also given of a new model of a disease propagated by a vector where these integral conditions play an important role.