Kidney ultrastructural lesions in dogs experimentally infected with Dirofilaria immitis (Leidy, 1856)

Kidneys of 16 beagles with experimentally induced heartworm (Dirofilaria immitis) infections and 4 heartworm-nai;ve dogs were studied by light and electron microscopy. The infections were induced either by subcutaneous injection of infective larvae or by the transplantation of adult parasites, and infection periods varied from 111 to 818 days and 365 to 923 days, respectively. One control group of heartworm-na?ve dogs and four groups of heartworm-infected dogs, which were divided according to the type and the length of infection, were used. In the infected dogs, thickening of the glomerular basement membrane (GBM), the presence of dense deposits in the GBM, and foot process effacement were the most frequent lesions observed. In some dogs, electron dense deposits were seen in the GBM and the mesangium and/or enlargement of the mesangial matrix could be characterized. The longer the infection period, the thicker the GBM and the more common the occurrence of foot process effacement. In general, these alterations were more evident in animals that had been infected for more than 1 year, had high microfilaremia, and had 14 or more parasites in the main pulmonary artery and its branches. The presence of dense deposits suggests that the pathogenesis of kidney disease in dirofilariasis is associated with deposits of immune complexes in the membrane. The finding of ultrastructural changes in dogs with early prepatent infections suggests that immature heartworms, as well as microfilariae and possibly adult worms, contribute to the glomerulonephropathy.     

Collection and short-term preservation of semen from free-ranging eastern grey kangaroos (Macropus giganteus: Macropodidae)

Objectives To evaluate electro-ejaculation of free-range eastern grey kangaroos in the field and assess the efficacy of four diluents to preserve sperm motility over a 48-h period at 5°C.
Procedure and design Under gaseous anaesthesia, 25 free-range kangaroos were electro-ejaculated and characteristics of the ejaculate noted. Spermatozoa obtained from eight ejaculates were diluted in phosphate buffered saline containing various combinations of egg yolk and glucose and refrigerated at 5°C for 48 h.
Results Spermatozoa were recovered from 24 of 28 ejaculates. Mean (± SEM) semen volume (mL) and pH were 25.0 ± 1.9 and 7.1 ± 0.1 respectively. The forward motility (%), rate of movement of sperm (0 to 5) and sperm concentration (x 10⁶/mL) were 77.4 ± 1.5, 3.8 ± 0.9 and 31.2 ± 7.3 respectively. There was no significant difference between the four diluents in their ability to maintain forward motility of spermatozoa over 48 h. However, rate of movement over the same period was significantly (P < 0.01) improved when sperm were diluted in phosphate buffered saline containing 10% egg yolk.
Conclusions Electro-ejaculation is a safe and reliable method for collecting semen from free-ranging eastern grey kangaroos. Preliminary attempts at short-term preservation showed that the motility of kangaroo spermatozoa could be adequately stored for 24 h and that the addition of egg yolk to the semen diluent was beneficial for improving the rate of sperm movement.     

Epidemic of blindness in kangaroos - evidence of a viral aetiology

OBJECTIVE: To determine the cause of an epidemic of blindness in kangaroos. DESIGN AND PROCEDURES: Laboratory examinations were made of eyes and brains of a large number of kangaroos using serological, virological, histopathological, electron microscopical, immunohistochemical methods, and PCR with cDNA sequencing. In addition, potential insect viral vectors identified during the disease outbreak were examined for specific viral genomic sequences. SAMPLE POPULATION: For histopathological analysis, 55 apparently blind and 18 apparently normal wild kangaroos and wallabies were obtained from New South Wales, Victoria, South Australia, and Western Australia. A total of 437 wild kangaroos and wallabies (including 23 animals with apparent blindness) were examined serologically. RESULTS: Orbiviruses of the Wallal and Warrego serogroups were isolated from kangaroos affected with blindness in a major epidemic in south-eastern Australia in 1994 and 1995 and extending to Western Australia in 1995/96. Histopathological examinations showed severe degeneration and inflammation in the eyes, and mild inflammation in the brains. In affected retinas, Wallal virus antigen was detected by immunohistochemical analysis and orbiviruses were seen in electron microscopy. There was serological variation in the newly isolated Wallal virus from archival Wallal virus that had been isolated in northern Australia. There were also variations of up to 20% in genotype sequence from the reference archival virus. Polymerase chain reactions showed that Wallal virus was present during the epidemic in three species of midges, Culicoides austropalpalis, C dycei and C marksi. Wallal virus nucleic acid was also detected by PCR in a paraffin-embedded retina taken from a blind kangaroo in 1975. CONCLUSION: Wallal virus and perhaps also Warrego virus are the cause of the outbreak of blindness in kangaroos. Other viruses may also be involved, but the evidence in this paper indicates a variant of Wallal virus, an orbivirus transmitted by midges, has the strongest aetiological association, and immunohistochemical analysis implicates it as the most damaging factor in the affected eyes.     

Intelligence quotient pattern over age: comparisons among siblings and parent-child pairs

Comparisons between sibling and parent-child pairs with unrelated control pairs matched for year of birth and parental education were made to determine the relative heritability of the general level of intelligence quotient as opposed to that of the sequential pattern of IQ change over age (3 to 12 years). There was greater similarity among related siblings relative to matched controls for general level than for pattern of IQ over age. Relationships between the IQ's of children and that of their parents as children were not consistent across age.     

Soft scald induced damage of chicken skin

1. The combination of a soft scald treatment and mechanical plucking did not cause significant removal of epidermal tissue from the skin surface of commercially processed meat chickens.

2. Scalding and plucking caused partial separation of the stratum corneum from underlying germinative tissue as well as significant damage to cell integrity of the latter tissue, especially in areas close to the epidermal/dermal tissue boundary.     

Effect of Cryopreservation on the Sperm DNA Fragmentation Dynamics of the Bottlenose Dolphin (Tursiops truncatus)

Sperm DNA fragmentation is one of the major causes of infertility; the sperm chromatin dispersion test (SCDt) evaluates this parameter and offers the advantage of species‐specific validated protocol and ease of use under field conditions. The main purpose of this study was to evaluate sperm DNA fragmentation dynamics in both fresh and post‐thaw bottlenose dolphin sperm using the SCDt following different cryopreservation protocols to gain new information about the post‐thaw differential sperm DNA longevity in this species. Fresh and cryopreserved semen samples from five bottlenose dolphins were examined for sperm DNA fragmentation dynamics using the SCDt (Halomax^®). Sperm DNA fragmentation was assessed immediately at collection and following cryopreservation (T0) and then after 0.5, 1, 4, 8, 24, 48 and 72 h incubation at 37°C. Serially collected ejaculates from four dolphins were frozen using different cryopreservation protocols in a TES‐TRIS‐fructose buffer (TTF), an egg‐yolk‐free vegetable lipid LP1 buffer (LP1) and human sperm preservation medium (HSPM). Fresh ejaculated spermatozoa initially showed low levels of DNA fragmentation for up to 48 h. Lower Sperm DNA fragmentation (SDF) was found in the second fresh ejaculate compared to the first when more than one sample was collected on the same day (p < 0.05); this difference was not apparent in any other seminal characteristic. While there was no difference observed in SDF between fresh and frozen–thawed sperm using the different cryopreservation protocols immediately after thawing (T0), frozen–thawed spermatozoa incubated at 37°C showed an increase in the rate of SDF after 24 h. Sperm frozen in the LP1^? buffer had higher levels (p < 0.05) of DNA fragmentation after 24‐ and 48‐h incubation than those frozen in TTF or HSPM. No correlation was found between any seminal characteristic and DNA fragmentation in either fresh and/or frozen–thawed samples.     

Efficacy of long-term monthly administration of ivermectin on the progress of naturally acquired heartworm infections in dogs

This study was designed to evaluate the efficacy of prolonged monthly ivermectin treatment against Dirofilaria immitis in client-owned dogs with naturally acquired infections and to clinically monitor the animal's response to the slow killing of heartworms, with death of the worms distributed over a period of up to 2 years. A total of 17 male and female dogs of different breeds and ages were used. Prior to treatment, all of the dogs tested positive for heartworm antigen (Ag) and all but two had microfilariae (mf). The dogs were randomly allocated to one group of seven dogs which received a commercial formulation of ivermectin (minimum, 6 mcg IVM/kg) plus pyrantel (minimum, 5 mg PP/kg) (Heartgard Plus Chewables, Merial, Ltd.), another group of seven dogs which received a commercial formulation of IVM (min, 6 mcg/kg) (Heartgard Chewables, Merial Ltd.), and a group of three dogs which served as an untreated controls. All dogs were evaluated prior to initiation of treatment and thereafter at 3- to 5-month-intervals for mf, Ag, and radiographic and echocardiographic findings. All of the 17 dogs, with the exception of two dogs in the IVM group, had circulating mf of D. immitis prior to the 1st monthly dose, and a few also had mf of Dirofilaria repens. After 4 monthly doses, only one dog in the IVM/PP group and two dogs in the IVM group had a patent heartworm infection, and no heartworm mf were seen in the 14 treated dogs thereafter. After 10 monthly doses, the number of Ag-positive dogs in both of the treated groups decreased gradually. Efficacy, based on the reduction in number of Ag-positive dogs, was similar for the IVM/PP and IVM groups, with overall efficacy scores for the 14 dogs of 21, 21, 43, and 71% after 10, 14, 19, and 24 monthly doses, respectively. Two of the seven dogs treated with IVM/PP, one of the seven treated with IVM, and two of the three untreated controls showed echocardiographic evidence of a parasitic burden prior to treatment, and all of these scores had decreased by the end of the study. Only one dog (IVM/PP group) had a cardiovascular pattern of heartworm disease by echocardiography prior to treatment, but this dog's score increased to two and the scores of two additional dogs increased from zero to two (IVM group) or three (IVM/PP group) by the end of the study. Only 1 (IVM/PP group) of the 17 dogs showed a pulmonary pattern of heartworm disease by radiography prior to treatment, but this dog's score increased to three by the end of the study. The radiographic scores of two additional dogs in the treated groups increased from zero to three (IVM/PP) or two (IVM) by the end of the study. Thus, monthly administration of IVM to dogs with clinical, radiographic or echocardiographic evidence of heartworm disease is ill-advised and such treatment of even the asymptomatic dog should be done only with much caution and frequent monitoring by the veterinarian.