Impact of soil erosion in disturbed tributary drainages on the benthic invertebrate fauna of Lake Tanganyika, East Africa

We analysed the species diversity and distribution of recently buried remains of larval Chironomidae (Insecta: non-biting midges) in bottom environments of Lake Tanganyika adjacent to pristine and disturbed tributary drainages, to investigate the ecological impact of sediment pollution caused by anthropogenic soil erosion. Within each of three drainage size classes (<10, 30-50, 50-162 km²), disturbance has resulted in similar shifts in chironomid species composition which appear to reflect expansion of coarse-grained, low-organic substrates into deeper water, at the expense of the soft organic muds which characterise the deep-water environment. Because the area of habitable lake bottom in Lake Tanganyika is bounded from below by the oxycline, these results indicate that sediment pollution negatively impacts the oxygenated deep-water environment of Lake Tanganyika, and that intensifying soil erosion in tributary drainages may eventually threaten the survival of endemic fish and mollusc species dependent on the habitat it provides. This study establishes the value of sub-fossil Chironomidae as biological indicators of ecosystem health in the large lakes of East Africa.     

Escapement success and patterns of downstream migration of female silver eel Anguilla anguilla in the River Meuse

Abstract – Downstream migration of female silver eel Anguilla anguilla (L.) was studied by remote telemetry in the lower part of the River Meuse (Belgium and the Netherlands) using a combination of nine detection stations and manual tracking. N = 31 eels (L_T 64–90 cm) were implanted with active transponders and released in 2007 into the River Berwijn, a small Belgian tributary of the River Meuse, 326 km from the North Sea. From August 2007 till April 2008, 13 eels (42%) started their downstream migration and were detected at two or more stations. Mean migration speed was 0.62 m·s^?1 (or 53 km·day^?1). Only two eels (15%) arrived at the North Sea, the others being held up or killed at hydroelectric power stations, caught by fishermen or by predators or stopped their migration and settled in the river delta. A majority (58%) of the eels classified as potential migrants did not start their migration and settled in the River Berwijn or upper Meuse as verified by additional manual tracking.     

Molecular detection of microbes in nasal tissue of dogs with idiopathic lymphoplasmacytic rhinitis

Lymphoplasmacytic rhinitis (LPR) is a common histologic finding in dogs with chronic nasal disease; however, potential etiologies of this disorder have not been examined. We investigated the hypothesis that specific microbes contribute to clinical disease in dogs with LPR. Paraffin-embedded nasal biopsies were obtained from 19 dogs with LPR, 10 dogs with nasal neoplasia, and 10 dogs with nasal aspergillosis. Nucleic acids were extracted from paraffin blocks, and real-time quantitative polymerase chain reaction (PCR) was employed for detection of target genes for bacterial and fungal DNA, canine adenovirus 2 (CAV-2), parainfluenza virus 3 (PI-3), Chlamydial Chlamydophila spp., and Bartonella spp. Conventional PCR was used for detection of Mycoplasma spp. Statistical analysis was performed using the Mann-Whitney U-test for nonparametric data, and significance was set at P < 0.05. DNA or RNA for CAV-2, PI-3, Bartonella, Mycoplasma, and Chlamydophila was not detected in any nasal biopsy. DNA loads for bacterial DNA did not differ among disease groups. Detection of fungal DNA in nasal biopsies was highest in dogs with aspergillosis (P < 0.0001); however, nasal biopsies of LPR dogs also displayed higher fungal DNA levels than samples from dogs with nasal neoplasia (P = 0.016). Detection of high levels of fungal DNA in nasal biopsies of dogs with LPR suggests that fungal organisms may be causally associated with the inflammation observed, although the possibility of entrapment or accumulation of fungi in the nasal cavity due to chronic inflammation cannot be excluded. Further investigations are required to elucidate the underlying etiopathogenesis of LPR.     

Brain Abscess in a 4-Month-Old Filly: A Case Report

Although recognized as a possible complication to sepsis, there are few published reports on brain abscesses in foals. This case report describes a 4-month-old Icelandic filly that, as a neonate, had a history of pyrexia and lameness, which resolved with antibiotic treatment. Approximately 3 months later, the foal developed neurological signs which were initially attributed to trauma; she was referred for further investigation. The clinical signs were consistent with a lesion of the right forebrain. Computed tomography examination revealed a mass, approximately 6 cm in diameter, located in the right cerebral hemisphere craniolateral to the right lateral ventricle. Because of the poor prognosis, the foal was killed, and a postmortem was performed. The findings confirmed the presence of an abscess of the right cerebral hemisphere, leading to severe atrophy of the cortex and dilation of both lateral ventricles. The left hemisphere was moderate-to-severe atrophic and had displaced to the left. Streptococcus equi subspecies zooepidemicus was isolated in pure culture from the abscess. The clinical features of the foal were compared with the pathological findings.     

What has happened in norway after the ban of avoparcin? Consumption of antimicrobials by poultry

When avoparcin was prohibited for use as feed additive in poultry in Norway on 31 May 1995, an increased incidence of Clostridium perfringens-associated necrotic enteritis (NE) and an increase in the use of antibacterial (AB) drug therapy in meat-type poultry was expected. The consumption of AB drugs for use against NE in poultry in the period 1990-2001 was investigated by use of sales statistics at the drug-wholesaler level. Defined daily dose (DDD) per kg live weight poultry was the unit of measurement for drug use (to correct for differences in the dosages). Sales figures of the AB drugs were converted to number of DDDpoultry sold for the numbers of broilers at risk (broilers were 97% of the slaughter poultry). Estimated annual percentages of the broilers treated against NE increased abruptly after the avoparcin ban--but in 1996, this figure declined to the same level as before the ban and has remained at that low level since then. In November 1995, narasin was approved temporarily as an ionophore feed additive (IFA) in broilers. The usage patterns of IFAs in broilers were measured as the weight of feed to which an IFA was added per broiler chicken produced. In 1996-2001, the IFAs used in broilers were predominantly narasin. We note that the temporary increase in NE after the avoparcin ban coincide with the period before narasin became available. The increase in the consumption of AB drugs for the treatment of NE in poultry following the avoparcin ban has been negligible.     

Malignant Sertoli cell tumor in the retained abdominal testis of a unilaterally cryptorchid horse

A 13-year-old Morgan gelding was evaluated because of a mass in the caudal region of the abdomen. The horse had been presumed to be a gelding, but necropsy findings revealed a retained testis in the right retroperitoneal space. Histologically, the retained testis contained neoplastic cells; metastases were identified in the liver, spleen, lungs, and sublumbar lymph nodes. Immunohistochemical examination of the testis and metastatic tissues confirmed the diagnosis of malignant Sertoli cell tumor. Testicular neoplasms are infrequently reported in stallions. Seminomas are most commonly reported, whereas Sertoli cell tumors are considered to be rare. Typical biological behavior of Sertoli cell tumors in horses is unknown. To the authors' knowledge, there have been 2 reports of Sertoli cell tumors in horses; the tumors developed in descended testes, and 1 tumor was malignant.     

Use of vitamin B12 in joint lavage for determination of dilution factors of canine synovial fluid

OBJECTIVE: To test a modified saline (0.9% NaCl) solution joint washing (lavage) technique that includes the use of vitamin B12 as an internal marker for the evaluation of synovial fluid dilution in lavage samples from canine joints. SAMPLE POPULATION: 9 plasma samples obtained from blood samples of 9 healthy dogs and 9 synovial fluid samples aspirated from stifle joints of 9 cadaveric dogs. PROCEDURE: Photometric absorbances of 25% vitamin B12 solution, canine synovial fluid, and canine plasma were measured in a spectrophotometer to establish an optimal wavelength for analysis. Canine synovial fluid and plasma samples were mixed with the 25% vitamin B12 solution to obtain 1%, 3%, 5%, 10%, 20%, and 50% solutions of synovial fluid or plasma. Diluted synovial fluid and plasma samples were used to simulate joint lavage samples and to examine the possible interference of these substances (synovial fluid or plasma) with the absorbance of the 25% vitamin B12 solution in photometric analysis. RESULTS: The optimal wavelength was found to be at 550 nm. Canine synovial fluid and plasma samples did not interfere with the absorbance measurements of the 25% vitamin B12 solution up to a 50% dilution of plasma or synovial fluid. CONCLUSIONS AND CLINICAL RELEVANCE: The modified saline solution joint lavage method with the use of a 25% vitamin B12 solution as an internal standard provides an accurate and reliable technique for the evaluation of synovial fluid dilution in lavage samples from canine joints.