Diminazene aceturate is one of a limited number of drugs currently being used in animals to treat the tsetse fly-transmitted protozoal disease, African trypanosomiasis. Efficacy of the drug at the recommended single IM administered doses of 3.5 and 7.0 mg/kg of body weight is widely acknowledged. However, resistance to the drug at these dosages has been reported. Although the mechanisms of resistance to diminazene are poorly understood, field and experimental data indicate that it may develop naturally through administration of subcurative doses, or as a result of cross-resistance. Evidence from other experimental studies indicates that there are additional mechanisms by which trypanosomes may develop resistance to diminazene aceturate. For instance, some populations ot Trypanosoma brucei and T. vivax are refractory to treatment because of their ability to invade the CNS, a site that is believed to be poorly accessible to diminazene. Furthermore, in recent studies carried out in goats, it has been documented that the ability of T. Congolense IL 3274 to survive treatment with diminazene depends on the stage of infection when treatment is administered; populations of the parasite reappeared in animals that were treated on day 19 after tsetse fly challenge, whereas all goats were cured when treated on day 1 of infection. Because trypanosomes are confined to the skin on day 1 after infection, but thereafter invade the blood circulation, it is possible that the efficacy of the treatment on day 1 is attributable to exposure of the small number of parasites, relative to later stages of infection, to higher concentrations of drug than those attained in blood. The objective of the study reported here was to determine whether diminazene's pharmacokinetics differ between plasma and lymph draining the skin of goats and therefore account for the variation in therapeutic activity of the drug at different stages of a tsetse fly-transmitted infection. Peripheral lymph was used for this work because it appears to be identical in composition to tissue interstitial fluid, into which trypanosomes are inoculated by infected tsetse flies when feeding.

Diarrhoea in growing-finishing pigs is a common problem of commercial pig farms. Among many causative factors, porcine circovirus type 2 (PCV2) is one considered an important pathogen in modern pig production. The aim of the study was to verify if PCV2 was responsible for antibiotic non-responsive diarrhoea and wasting in pigs. A total of 13 dead pigs aged between 12 and 15 weeks from three Polish farms with persistent herd symptoms suggestive of PCV2 infection were provided for evaluation. Sections of lymph nodes and intestines were analysed by in situ hybridization (ISH) for PCV2 and histopathological examination. Faeces and intestinal scrapings were tested for Lawsonia intracellularis and Brachyspira hyodysenteriae by real-time PCR and for parasitic infection by flotation and decantation. ISH and histopathological examination showed that all pigs were PCV2 systemic disease negative. Swine dysentery was confirmed by real-time PCR on two farms, and proliferative enteropathy on one farm. In histological examinations, erosions of the caecal and colonic mucosa were found, together with cysts and trophozoites of Balantidium coli. The protozoa were present in the intestinal lumen and mucosa. B. coli cysts were identified in faeces from all examined pigs. These results suggest that monitoring of B. coli infections should be an additional measure of control and prevention of gastrointestinal tract disorders in modern swine husbandry.

Corynebacterium pseudotuberculosis is the causative agent of caseous lymphadenitis (CLA) a contagious and infectious disease in smallruminants. This report describes a case of CLA in a Boer cross goat infected with Corynebacterium pseudotuberculosis. The manifestation of abscess in the superficial lymph node presented as a mass ofapproximately 5 cm by 5 cm in diameter at the base of the ear. The mass was solid and non-movable upon palpation. The mass was incised and the caseous material was aspirated and sent to the bacteriologylaboratory where Corynebacterium pseudotuberculosis was isolated. Thewound was cleaned and flushed with diluted chlorhexidine and iodine solutions daily. This procedure aids in the complete healing of the wound after a few weeks. However, the agent of the disease persistsin the animal in its entire life and culling is recommended to prevent the spread of the disease in the herd.

Objective-To develop a system for analysis of immune response variables in the lymph draining the lung and to establish baseline data for clinically normal calves. Design-Surgery was performed on 6 calves to insert a cannula into the efferent lymphatic duct of the caudal mediastinal lymph node to create a long-term thoracic lymph fistula draining to the exterior. Lymph was collected daily, and on the fifth postoperative day, calves were exposed to an aerosol of cell culture medium (mock infection). For the next 10 days, lymph was collected for analysis and, on the tenth day, necropsy was performed. Animals-Six 6- to 8-week-old Holstein bull calves. Procedure-Daily lymph samples were evaluated for: flow rate; total and differential cell counts; and IgG, IgM, IgA, IgE, and protein concentrations. On days -4, -1, 1, 4, 7, and 10, cells were stained and quantitated by fluorescence-activated cell sorter analysis for T, B, CD4+, and CD8+ cells. Blood lymphocytes were evaluated on days -1 and 10 for comparison. Results-Flow was established for up to 25 days, with a mean rate between 11 and 22 ml/h. Protein concentrations in lymph and plasma did not indicate a protein drain. Although mean lymphocyte counts reflected a slight gradual decrease in lymph lymphocytes, this effect was not apparent in every calf, nor was the effect seen in blood lymphocytes. There were no significant changes in IgG, IgM, IgA, or IgE concentration, with the exception of IgA concentration in 1 calf that developed an abscess at the cannulation site. The T-cell subset absolute numbers of CD4+ and CD8+ cells decreased slightly over time, but the CD4+-to-CD8+ cell ratio remained almost constant at near 2. Conclusion-Creation of a thoracic lymphatic fistula appears to be a useful technique for studying effects of lung infection on immunologic variables, with potential application to bacterial and viral respiratory tract diseases.

Alterations in the various leukocyte populations in milk, blood, and mammary lymph were studied by use of the flow cytometric method during acute mastitis episodes induced by endotoxin infusion (50 microgram of lipopolysaccharide of Salmonella typhimurium SH 4809) via the teat canal. Lymph samples were collected via a semipermanent catheter from an afferent duct to the supramammary lymph node. Milk somatic cell count increased at 4 hours after infusion of endotoxin. Neutrophils were the predominant cell population for up to 59 hours after infusion. Numbers of lymphocytes and monocytes-macrophages in milk also increased after the endotoxin infusion. The total cell count in milk started to decrease during the third postinfusion day and returned to preinfusion values during the fourth day. Lymphocyte numbers remained high for about 1 week after the infusion, and lymphocytes were the predominant cell population between postinfusion days 4 and 8. Total blood leukocyte count decreased during the first 6 hours after infusion, followed by an increase until postinfusion hour 31. The proportion of neutrophils in blood increased during the first day, whereas that of lymphocytes decreased. Lymph flow rate and leukocyte numbers in lymph increased after endotoxin infusion. The proportion of neutrophils in the lymph increased during the first 6 hours, whereas that of lymphocytes decreased. After postinfusion hour 6, the inverse course of events was seen.

Microvascular permeability characteristics were evaluated in digits of 7 adult horses. After capillaries were isolated and an extracorpeal perfusion circuit for the digit was established, a lymphatic vessel draining the distal portion of the phalangeal region was cannulated at the level of the coronary band. Venous pressure was increased in a stepwise manner, and lymph flow, lymph protein concentration (Cl), and plasma protein concentration (Cp) were determined after measured variables were allowed to reach steady state. Lymph-to-plasma protein concentration ratios (Cl/Cp) and lymph and plasma oncotic pressures were determined from samples collected during steady state. The osmotic reflection coefficient was determined after Cl/Cp became constant, regardless of increasing lymph flow, and was expressed as 1 - Cl/Cp. The osmotic reflection coefficient for the digit was 0.67. Seemingly, the microvasculature bed of the digit was relatively permeable and could maintain only 67% of the endogenous macromolecules within the vasculature.

Integrin alpha-v/beta3 (αvβ3) recognizes arginine-glycine-aspartic acid (RGD) sequences and has important functions in cell adhesion, signaling, and survival. However, the expression of integrin αvβ3 in the equine lungs and jejunum is not well understood. The objective of this study was to explore the hitherto unknown expression of integrin αvβ3 in the lungs and jejuna of the horse using light and electron immunocytochemistry. Immunohistochemistry showed integrin αvβ3 on the epithelium, the immune cells in Peyer's patches, the smooth muscle, and the endothelium of equine jejuna. In equine lungs, we recognized integrin αvβ3 on the endothelium of blood vessels, the alveolar septa, the bronchial lymph nodes, and the cartilages, although the expression of integrin αvβ3 was weak on the epithelium of bronchioles. In conclusion, these are the first data to show the expression of integrin αvβ3 in equine lungs and jejuna.