Analysis of Amblyomma surveillance data in the Caribbean: Lessons for future control programmes

Amblyomma variegatum, the Tropical Bont Tick (TBT), is the principal vector of heartwater and is associated with dermatophilosis, major causes of losses in animal production and mortality in Caribbean livestock. From 1995 to 2007, the Caribbean Amblyomma Programme (CAP) supported treatment and surveillance activities in 11 islands of the Eastern Caribbean with an initial objective of eradicating TBT. In addition to control activities, surveillance data were collected between 1997 and 2006 in a unique regional database. We report the analysis of the surveillance data from four islands (Nevis, St Kitts, St Lucia, and Barbados) where control and surveillance followed the initial protocol and where enough data were collected. We describe the evolution of TBT infestation levels and the efforts carried out throughout the surveillance period. Logistic regression identified factors associated with herds found infested with TBT. Overall, treatment programmes were associated with a decrease in proportion of TBT-infested farms. High surveillance efforts were carried out throughout the 1997–2007 period for all island of interest, but inadequate level of surveillance was observed in several quarters especially for St Kitts. Third quarter of the year, as indication of adult TBT seasonality on livestock, was significantly associated with the risk of detecting TBT in Nevis and St Kitts livestock farms. Also, presence of cattle in Nevis farms was shown associated with an increasing probability of farms being declared TBT-infested. Outcomes of these analyses provide basis for recommendations to improve future national and regional control and surveillance activities. This analysis demonstrates the usefulness of long term and adequate surveillance data for control programmes and identification of factors associated with risk of having infested herds.     

In vitro effects of plant and mushroom extracts on immunological function of chicken lymphocytes and macrophages

1.?The present study was conducted to examine the effects of organic extracts from milk thistle (Silybum marianum), turmeric (Curcuma longa), reishi mushroom (Ganoderma lucidum), and shiitake mushroom (Lentinus edodes) on innate immunity and tumor cell viability.

2.?Innate immunity was measured by lymphocyte proliferation and nitric oxide production by macrophages, and the inhibitory effect on tumor cell growth was assessed using a non-radioactive assay. For measuring the cytokine levels in the HD11 macrophages which were treated with extracts of turmeric or shiitake mushroom, the levels of mRNAs for interferon-α (IFN- α), interleukin-1β (IL-1β), IL-6, IL-12, IL-15, IL-18, and tumor necrosis factor superfamily 15 (TNFSF15) were quantified by real time RT-PCR.

3.?In vitro culture of chicken spleen lymphocytes with extracts of milk thistle, turmeric, and shiitake and reishi mushrooms induced significantly higher cell proliferation compared with the untreated control cells. Stimulation of macrophages with extracts of milk thistle and shiitake and reishi mushrooms, but not turmeric, resulted in robust nitric oxide production to levels that were similar with those induced by recombinant chicken interferon-γ. All extracts uniformly inhibited the growth of chicken tumor cells in vitro at the concentration of 6·3 through 100 µg/ml. Finally, the levels of mRNAs encoding IL-1β, IL-6, IL-12, IL-18, and TNFSF15 were enhanced in macrophages that were treated with extracts of turmeric or shiitake mushroom compared with the untreated control.

4.?These results document the immunologically-based enhancement of innate immunity in chickens by extracts of plants and mushrooms with known medicinal properties in vitro. In vivo studies are being planned to delineate the cellular and molecular mechanisms responsible for their mechanism of action.     

Cytochrome P450 3A, NADPH cytochrome P450 reductase and cytochrome b5 in the upper airways in horse

Gene and protein expression as well as catalytic activity of cytochrome P450 (CYP) 3A were studied in the nasal olfactory and respiratory mucosa and the tracheal mucosa of the horse. We also examined the activity of NADPH cytochrome P450 reductase (NADPH P450 reductase), the amount of cytochrome b(5) and the total CYP content in these tissues. Comparative values for the above were obtained using liver as a control. The CYP3A related catalytic activity in the tissues of the upper airways was considerably higher than in the liver. The CYP3A gene and protein expression, on the other hand, was higher in the liver than in the upper airway tissues. Thus, the pattern of CYP3A metabolic activity does not correlate with the CYP3A gene and protein expression. Our results showed that the activity of NADPH P450 reductase and the level of cytochrome b(5) in the relation to the gene and protein expression of CYP3A were higher in the tissues of the upper airways than in the liver. It is concluded that CYP3A related metabolism in horse is not solely dependent on the expression of the enzyme but also on adequate levels of NADPH P450 reductase and cytochrome b(5).     

Evaluation of a new strategy to modulate skeletal development in Thoroughbred performance horses by imposing track-based exercise during growth

REASON FOR PERFORMING STUDY: No data exist on the intensity of exercise required or on possible harmful effects of increasing exercise in foals over the natural level when free at pasture. OBJECTIVES: To investigate whether an increase in workload over free pasture exercise in the period from directly after birth to the start of training is tolerated by Thoroughbred (TB) foals without increasing injury rate or producing other undesired side effects. METHODS: Thirty-three TB foals were allocated to one of 2 exercise groups directly after birth. One group (PASTEX) was raised on pasture and the other (CONDEX) kept under identical circumstances, but was additionally subjected to an exercise protocol of gradually increasing intensity. Foals were monitored periodically and scored for the presence of clinical signs related to the musculoskeletal system (joint effusion, pain at flexion, occurrence of physeal swelling), and radiographs taken at the end of the conditioning phase. Also, behavioural studies were performed to detect any changes in behaviour related to the exercise programme. Cortisol levels were measured in both groups, to assess the level of stress. RESULTS: Workload in the CONDEX group was significantly higher than in the PASTEX group (approximately 30%). Conditioning increased the likelihood for joint effusion in the antebrachiocarpal joint, but reduced tarsocrural effusion and physeal swelling at the lateral distal radius, the third metacarpal bone (medial aspect) and lateral and medial aspects of the third metatarsal bone. CONCLUSIONS: The 30% increase in workload did not affect the animals' welfare, effects of conditioning exercise on clinical musculoskeletal health were few and there were no adverse effects. POTENTIAL RELEVANCE: This study supports the feasibility of imposing early conditioning exercise in horses and is a benchmark for its effects on the development of equine musculoskeletal tissues.     

Canine lymphoproliferative disease characterized by lymphocytosis: immunophenotypic markers of prognosis

BACKGROUND: Canine lymphoproliferative disease often presents with lymphocytosis and is immunophenotypically diverse. HYPOTHESIS: Immunophenotype predicts prognosis in canine lymphoproliferative disorders involving circulating lymphocytosis. ANIMALS: Dogs that had peripheral blood evaluation performed by flow cytometry by the Clinical Immunology Service at Colorado State University between 2003 and 2005. METHODS: Outcome data regarding treatment and survival were sought on patients with lymphocytosis comprising a single lymphocyte subset. Ninety-six patients that met the inclusion criteria had sufficient follow-up information to be included in the study. RESULTS: Four main phenotypic classifications were found: CD8+ T-cell, CD21+ B-cell, CD4-8-5+ (aberrant T-cell phenotype), and CD34+ (undifferentiated progenitor). Expression of CD34 predicted poor outcome with median survival of 16 days (P < .0001) compared with other phenotypes. Within the CD8+ phenotype, dogs presenting with a lymphocytosis >30,000 lymphocytes/muL had significantly shorter median survival (131 days) than those presenting with <30,000 lymphocytes/muL (1098 days, P < .0008). Within the T-cell leukemias, there was no difference in outcome between dogs with CD4-8-5+ leukemia and dogs with the CD8+ T-cell phenotype nor was the loss of expression of the pan-leukocyte marker CD45 associated with decreased survival time. A CD21+ lymphocytosis composed of large cells was associated with shorter survival time (129 days) than those with smaller circulating cells (median survival not reached, P < .01). CONCLUSIONS AND CLINICAL IMPORTANCE: Immunophenotyping provides an objective method for determining prognosis in lymphoproliferative disorders characterized by lymphocytosis.     

Chlamydophila psittaci infections in humans during an outbreak of psittacosis from poultry in Germany

In 2005, an outbreak of severe respiratory disease in a mixed poultry flock that was infected with Chlamydophila (C.) psittaci led to dissemination of the infection to at least 100 small poultry farms in 11 districts of Central Germany. At the same time, a total of 24 persons in contact with poultry from one of the flocks reported flu-like symptoms to their physician, thus suggesting zoonotic transmission. Within 3 weeks, seven individuals had to be hospitalized, with three of them requiring intensive care. Analysis of ompA sequences from chlamydial isolates and directly from clinical samples revealed the presence of both genotype A and E/B of C. psittaci at the source of the outbreak and in contact flocks. Genotype A was also detected in the three severely ill patients. The findings of the present study demonstrate the high zoonotic potential of avian chlamydiae. To ensure speedy eradication of psittacosis in poultry flocks and effective treatment of infected humans, fast, sensitive and species-specific detection of the causative agent is essential, as well as close collaboration between regional public health services, attending physicians and the diagnostic laboratories involved.     

Nematode burdens of pastured cattle treated once at turnout with eprinomectin extended-release injection

The efficacy of eprinomectin in an extended-release injection (ERI) formulation was evaluated against infections with third-stage larvae or eggs of gastrointestinal and pulmonary nematodes in cattle under 120-day natural challenge conditions in a series of five studies conducted in the USA (three studies) and in Europe (two studies). For each study, 30 nematode-free (four studies) or 30 cattle harboring naturally acquired nematode infections (one study) were included. The cattle were of various breeds or crosses, weighed 107.5–273 kg prior to treatment and aged approximately 4–11 months. For each study, animals were blocked based on pre-treatment bodyweight and then randomly allocated to treatment: ERI vehicle (control) at 1 mL/50 kg bodyweight or Eprinomectin 5% (w/v) ERI at 1 mL/50 kg bodyweight (1.0 mg eprinomectin/kg) for a total of 15 and 15 animals in each group. Treatments were administered once on Day 0 by subcutaneous injection in front of the shoulder. In each study, all animals grazed one naturally contaminated pasture for 120 days. At regular intervals during the studies, fecal samples from all cattle were examined for nematode egg and larval counts. In four studies pairs of tracer cattle were used to monitor pasture infectivity at 28-day intervals before and/or during the grazing period. All calves were weighed before turnout onto pasture and at regular intervals until housing on Day 120. For parasite recovery, all study animals were humanely euthanized 27–30 days after removal from pasture.     

Pregnancy-related diabetes mellitus in two dogs

CASE SUMMARIES: Two cases of diabetes mellitus occurring in bitches in association with pregnancy are reported. In the first case, a bitch with suspected acromegaly developed diabetes mellitus within 2 weeks of the due date. Despite insulin therapy, euglycaemia was not achieved. Two live, small pups were delivered by elective Caesarean section but died within 2 days. Signs consistent with acromegaly resolved but diabetes mellitus was permanent in the bitch. In the second case, diabetic ketosis with severe gastrointestinal disease was diagnosed 2 days after Caesarean section was performed due to dystocia. The pups delivered all died within 5 days. The bitch recovered fully from diabetes mellitus within 2 weeks and has remained euglycaemic without insulin for a period of at least 18 months. CLINICAL RELEVANCE: These two cases demonstrate that diabetes mellitus can occur in association with pregnancy in dogs, that diabetic ketosis can occur during transient diabetes mellitus in dogs, and suggest that acromegaly may occur during pregnancy-related dioestrus in dogs. The scarcity of previous reports of this nature, however, suggests that such cases are unusual. Lack of prompt resolution of hyperglycaemia may result in secondary diabetes mellitus becoming permanent. Management should focus on immediate insulin therapy or ovariohysterectomy to minimise this risk. Even mild hyperglycaemia should not be ignored during pregnancy. The insulin antagonistic effects of pregnancy, stressful illness, surgery and dystocia can be enough to result in diabetic ketosis in the absence of permanent insulin deficiency. Maternal hyperglycaemia may contribute to adverse fetal outcomes in dogs but further study is required regarding the nature of the risk.