Transplacental Neospora caninum infection in dogs

A Beagle bitch was inoculated SC and IM with 1.5 million Neospora caninum tachyzoites on the 35th day of gestation. Eight pups were born alive 28 days after N caninum inoculation of the bitch. Pup 1 did not breathe and died while still enclosed in fetal membranes. Pup 2 died 2 days after birth (DAB). Pups 3, 4, and 5 were euthanatized on 2, 3, and 20 DAB, respectively, because they were hypothermic and not nursing. Pups 6, 7, and 8 remained clinically normal. Indirect fluorescent N caninum serum antibody titers were: less than 50 (pups 1 and 8 at 17 DAB, and the bitch before inoculation), 50 (pups 2 and 3 on 2 DAB), 200 (pups 6 and 7 on 17 DAB), and 800 (bitch on day 17 after parturition). Neospora caninum was recovered in cultured cells inoculated with placenta and tissues from all 5 pups necropsied, and N caninum was seen in histologic sections of the heart of pup 5. Results indicate that N caninum can be transplacentally transmitted in dogs.     

Neosporosis in Beagle dogs: clinical signs, diagnosis, treatment, isolation and genetic characterization of Neospora caninum

Clinical neosporosis was diagnosed in a litter of five pups born to a Beagle bitch from Virginia, USA. Four of the pups developed limb weakness starting at 4 weeks of age. The dogs were suspected to have neosporosis based on clinical signs and empirically treated with Clindamycin (75 mg, oral, twice daily, total 150 mg) starting at 9 weeks of age and the dosage was doubled at 13 weeks of age. Antibodies to Neospora caninum were detected in sera of the dam and pups when first tested serologically at the age of 4 months. The owner donated the pup with the worst clinical signs and the dam for research; both dogs were euthanized. Viable N. caninum was isolated in gamma interferon gene knock out (KO) mice and in cell culture from the pup killed at 137 days of age. Tissue cysts, but no tachyzoites, were found in histological sections of brain and muscles. The isolate was also identified as N. caninum by PCR and sequence analysis and designated NC-9. N. caninum was neither isolated by bioassay in KO mice nor found in histological sections of tissues of the bitch. Clinical signs in the remaining three pups improved considerably after a 6-month treatment with Clindamycin; N. caninum antibody titers were still persistent in these pups at 23 months of age. Results indicate that medication with Clindamycin can improve clinical condition but not eliminate N. caninum infection.     

Prolonged interval between parturition of normal live pups in a bitch

On day 64 after artificial insemination, a six-year-old primiparous briard bitch whelped three live pups between 05.00 and 08.00. It was presented at 11.00 on the same day with failure to complete parturition. On ultrasound examination, a normal live fetus was observed and the bitch was treated with oxytocin three times during the day (1.0, 2.0 and 2.0 iu intramuscularly), with no effect. The following day, a higher dose of oxytocin (5.0 iu) was administered intramuscularly at 11.00, after a uterine ultrasound examination confirmed viability of the fetus. At 18.00 of the same day, the bitch whelped the fourth normal live pup, 37 hours after initiation of parturition and 34 hours after expulsion of the last fetus. Effectiveness of oxytocin and normal versus prolonged parturition due to uterine inertia are discussed.     

Fenbendazole treatment of pregnant bitches to reduce prenatal and lactogenic infections of Toxocara canis and Ancylostoma caninum in pups

A granulated formulation of fenbendazole was tested in a total of 23 treated and control, pregnant, parasite-free Beagle bitches experimentally infected with Toxocara canis and Ancylostoma caninum. The drug was administered to each treated bitch once daily in canned dog food at a dosage of 50 mg/kg body weight. Each of 2 treatment regimens tested was initiated on the 40th day of pregnancy. One regimen involved daily treatment continuing through the 14th postpartum day, and it resulted in 89% fewer ascarids and 99% fewer hookworms in pups born to medicated bitches, as compared with pups born to unmedicated controls. The other regimen of treatment, which was stopped on the day of parturition, was less effective in reducing ascarid and hookworm burdens (64% and 88% reductions, respectively). Three to 5 bitches from each of the treatment and control groups were allowed to whelp a 2nd litter without further treatment or further exposure to parasite infections. Hookworm burdens in 2nd-litter pups born of bitches that had initially received fenbendazole through the 14th postpartum day were significantly lower (P < 0.01; 85% reduction), when compared with the 2nd-litter control pups. All other parasite burdens were not significantly different. It was concluded that granulated fenbendazole is effective in reducing burdens of Ancylostoma caninum and Toxocara canis in newborn pups when the bitch is treated during the last third of pregnancy, especially when treatment (50 mg/kg/day) extends from the 40th day of pregnancy through the 14th postpartum day.     

Biology, pathogenicity, diagnosis and control of Ancylostoma caninum]

Infections with Ancylostoma caninum are transmitted orally or percutaneously. The transmission of infectious stages with the milk of particular importance for the distribution of the species. It occurs during the dissemination of larvae that follows every infection as well as after reactivation of resting somatic larvae in the bitch at the end of the pregnancy. The galactogenic transmission of larvae occurs even when, due to existing immunity, no patent infections develop in the bitch. Immunity does not or only to a low extent influence impatient infections or the migration of reactivated somatic larvae. It also allows a limited reestablishment of a deposit of larvae in the bitch. Following percutaneous infection dermatitis occurs in the area of larval penetration and the lung is affected by migrating larvae. Intestinal stages of Ancylostoma caninum damage the host by ingestion of the mucosa of the small intestine and withdrawal of blood. Main symptoms of ancylostomiasis are a mucous haemorrhagic diarrhoea and anaemia, that become visible 8 to 10 days post infection. The examination for impatient infections with Ancylostoma caninum can be done by immunofluorescence and ELISA. With both methods antibodies against third stage larvae can be detected from the first or second week post infection onward. Patent infections with Ancylostoma caninum can easily be detected by faecal examination for the presence of the characteristic oval, thin-walled eggs containing few blastomeres. Galactogenic infections with Ancylostoma caninum can be prevented or reduced by a regular treatment of the bitch with albendazole, fenbendazole or oxfendazole during the activation of larvae in the last third of the pregnancy or by repeated treatment with ivermectin shortly before and after birth. To prevent patent infections, galactogenic infected puppies have to be treated early and repeatedly.     

Experimental and naturally occurring transplacental transmission of canine distemper virus

In the present study, 2 different effects of experimentally induced infection with virulent canine distemper virus (CDV) on pregnant CDV-susceptible dogs were studied. In 1 bitch, abortion occurred 7 days after viral inoculation and there was no evidence of fetal infection. Another bitch had subclinical infection and delivered 3 CDV-infected pups. Sequential clinical, immunologic, and virologic studies of a litter of gnotobiotic pups (3rd bitch) that were congenitally infected with CDV demonstrated the heightened susceptibility to CDV in the neonatal period. The data presented add canine distemper to the list of transplacental infectious diseases in the canine species.     

Haematological and serological data from dogs raised worm-free and monospecifically infected with helminths

Pups free from helminth infection were obtained by treating the bitch prior to parturition, and the bitch and her pups after whelping, with oxfendazole and praziquantel. They were then housed in an area free from contamination with helminth eggs. Freedom from infection was confirmed by necropsy examinations and by serological tests using the Enzyme Linked Immunosorbent Assay (ELISA). Groups of pups were infected with Toxocara canis, Echinococcus granulosus, Taenia ovis, T. pisiformis and T. hydatigena and bled at 5-day intervals. Haematological examinations and measurement of serum proteins were performed on blood samples obtained throughout 30 days of infection. Levels of serum proteins were not significantly altered in any infection. Pups infected with T. canis showed a marked increase in numbers of circulating eosinophils during the phase of larval migration through the liver and lungs; they also showed marked antibody responses to T. canis larval ES antigen. Haematological values were not significantly altered in any other pups.     

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. Tw o 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.     

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.     

Neonatal Neospora caninum infection in dogs: isolation of the causative agent and experimental transmission

Neospora caninum infection was diagnosed in 5 young dogs from 2 litters with a common parentage. The pups were born healthy, but developed hind limb paresis 5 to 8 weeks after birth. The predominant lesions were polyradiculoneuritis and granulomatous polymyositis. Neospora caninum was seen microscopically in sections of naturally infected pups, and was isolated in cell cultures, mice, and dogs inoculated with infected canine tissues. Antibodies to N caninum were detected in sera of infected dogs by indirect fluorescent antibody test.     

Management of apparent luteal insufficiency in a bitch.

Serum progesterone concentration in a pregnant bitch with suspected luteal insufficiency was monitored by use of a commercially available ELISA kit, and exogenous progesterone was administered as needed to enable the bitch to deliver normal-term pups. Progesterone in oil was administered at a dosage of 2 mg/kg of body weight at 72-hour intervals. The bitch delivered 2 clinically normal male pups and 1 mummified female pup within 12 hours after the exogenous progesterone was calculated to have been metabolized.     

Experimental transplacental transmission of canine herpesvirus in pregnant bitches during the second trimester of gestation

The effects of canine herpesvirus (CHV) on fetuses were studied after IV inoculation of pregnant bitches in the 2nd trimester of gestation. Cesarean sections were performed on 2 bitches that were inoculated with CHV on the estimated 30th day of gestation. Bitch M-1 had 2 mummified fetuses and bitch M-2 had 4 mummified and 2 dead fetuses and 3 live-born pups. Infection by CHV was confirmed histopathologically by the presence of focal areas of necrosis associated with intranuclear inclusion bodies in heart muscle sections of 1 dead fetus; CHV was not recovered from other organs. Abortion occurred between the 2nd and 3rd week after inoculation of another pregnant bitch inoculated with CHV on the estimated 30th day of gestation. Two bitches inoculated with CHV on the estimated 40th day of gestation gave birth prematurely to 10 pups. The detection of characteristic herpesviral lesions in various organs and the reisolation of CHV from the liver, spleen, kidneys, and lungs of premature pups indicated CHV infection. Transplacental infection of fetal pups by CHV resulted in their death and subsequent mummification. It appears that abortion and premature birth also may occur in pregnant bitches infected during the 2nd trimester of gestation.     

Postural Influence on Systemic Blood Pressure in Large Full-term Pregnant Bitches during General Anesthesia

Effects of positioning on systemic blood pressure were evaluated in six full-term pregnant golden retriever bitches during general anesthesia. Two positions (dorsal and left lateral recumbency) were examined. Anesthesia was induced with thiamylal sodium and maintained with halothane in oxygen. Direct arterial blood pressures were recorded from the bitches in each position. Effects of positioning for each bitch during general anesthesia were reexamined after the bitch weaned its pups; thus, each bitch served as its own control. Maternal posture had no significant effect (p greater than 0.05) on systemic blood pressure. Pregnancy had no significant effect (p greater than 0.05) on systemic blood pressure. Supine hypotension did not occur in anesthetized large, full-term pregnant bitches. Dorsal recumbency was an acceptable position for cesarean sections performed with the patient under general anesthesia.     

First report of the use of meglumine antimoniate for treatment of canine leishmaniasis in a pregnant dog

Canine leishmaniasis during pregnancy is rarely reported, even in countries where the infection in dogs is endemic. The authors report a case of a 4 yr old bitch with leishmaniasis treated with meglumine antimoniate during pregnancy. The pregnancy and delivery were normal and the bitch presented improvement of the infection during treatment. Three puppies died within 2 days of birth and tested negative via real-time PCR for L. infantum. The two surviving puppies were followed clinically, serologically, and by real-time PCR until 1 yr of age with no evidence of congenital leishmaniasis. L. infantum DNA was detected with real-time PCR analysis of uterine tissue from the bitch at the time of ovariohysterectomy. PCR analysis was performed after an ovariohysterectomy of the bitch that was performed two months after parturition. Meglumine antimoniate use in the pregnant bitch may have prevented vertical transmission of leishmaniasis.     

Distemper encephalitis in pups after vaccination of the dam.

A five-year-old labrador bitch which had whelped 10 pups three days previously was given booster vaccination against distemper, adenovirus, parvovirus, parainfluenzavirus and leptospirosis. Eighteen days later, signs of central nervous system disease developed in some of the pups, five of which were ultimately euthanased. The cause of the nervous disease was found to be canine distemper, and serological studies showed that the infection was limited to some members of the litter, suggesting that the vaccinal rather than a field virus was more likely to have been responsible.     

Efficacy and toxicity of tamoxifen citrate for prevention and termination of pregnancy in bitches

Five groups of bitches were given tamoxifen citrate (1 mg/kg of body weight) orally twice daily for 10 days. Drug administration commenced during late proestrus, day 4 of estrus, day 2 of diestrus, day 15 of diestrus, or day 30 of diestrus (n = 4/group). Nineteen of the bitches accepted natural mating by 1 or more of 3 stud dogs of known fertility (1 bitch did not). Twenty days after cessation of drug administration, ovarian, uterine, and hepatic specimens were obtained from each bitch in 4 of the groups. Pregnancy proceeded to natural termination in bitches of the remaining group (diestrous day 30). Pregnancy was not detected in any bitch of the proestrus, estrous, or early diestrous groups. Of 4 bitches of each of the remaining groups (diestrous day 15 and diestrous day 30), 2 aborted fetuses and/or resorbed placental remnants; the other 2 bitches in each of these groups had normal-appearing fetuses (diestrous day-15 group) or clinically normal pups (diestrous day-30 group). Of the 20 bitches given tamoxifen citrate, 5 developed endometritis with or without pyometra, and 4 of these had ovarian cysts. Although tamoxifen citrate is effective for preventing or terminating pregnancy in the bitch, the regimen used in the study reported here was associated with high frequency of pathologic changes in the reproductive tract.     

Influence of Neospora caninum infection in BALB/c mice during pregnancy in post-natal development

The influence of Neospora caninum infection during pregnancy on the post-natal period has been poorly investigated. In a previous study, we suggested that infection with N. caninum during pregnancy could affect the normal post-natal development of the offspring. For this reason, in the present work we evaluated the influence of N. caninum infection in pregnant BALB/c mice at days 0, 7 and 14 of gestation (groups A, B and C, respectively) on the post-natal development of the offspring from birth to day 60 post-partum (PP). Morbidity and mortality, vertical transmission, and histopathological lesions were investigated. The humoral immune response (IgG) of pups was also evaluated. Results showed that infection with N. caninum during pregnancy had fatal consequences for pups, especially during mid-gestation (day 7). Infection provoked a delay in the general development of neonates, clinical signs compatible with neosporosis and severe histopathological lesions. A high mortality rate was found in all infected groups. A 69% of mortality rate was found in group A, a 100% in group B and a 46% in group C. Necrotizing encephalitis and multifocal hepatocellular necrosis were the most severe lesions found. All neonates, except four animals from group C, had antibodies against N. caninum but the immune response was not sufficient to control parasite infection. We have demonstrated that extension of the observation period after N. caninum infection permits a more accurate study of vertical transmission, the major route of parasite transmission, and mortality rates. We propose that infection at mid-gestation (day 7) in BALB/c mice and its study during the post-natal period constitutes a valuable experimental model for testing new chemotherapeutic agents and vaccines designed to protect against congenital neosporosis, in order to select effective protocols before its use on bovine.     

Use of fenbendazole suspension (10%) against experimental infections of Toxocara canis and Ancylostoma caninum in beagle pups

Eleven nematode-free Beagle pups were inoculated with Ancylostoma caninum and Toxocara canis; infection became patent 13 and 35 days later, respectively. Eight pups were treated with fenbendazole oral suspension (10%) at a dosage of 50 mg/kg of body weight/day for 3 days. The remaining three animals were unmedicated controls. The drug was effective in reducing both ascarid and hookworm burdens, and there was marked improvement in the clinical condition of treated pups as compared with unmedicated control pups. Natural expulsion of worms in control animals was 53% for ascarids and 2% for hookworms. Drug-related toxicosis was not observed in any of the medicated animals. It was concluded that fenbendazole oral suspension (10%) at the 50-mg/kg dosage is easily administered and is an effective drug for reducing nematode burdens in experimentally infected pups.     

An epizootic of peroneal and tibial neuropathy in Walker Hound pups

Early in life, Walker Hound pups from several litters, later determined to have peroneal and tibial neuropathy, had been given supplements of either evaporated milk and corn syrup mixed with well water or powdered bitch milk formula mixed with well water. Other pups not given supplements were not affected. Pelvic limb monoparesis, areflexia, analgesia, and muscular atrophy developed by 2 weeks of age. Abnormalities detected by light and electron microscopy included scattered swollen axons containing increased organelles and whorled neurofilaments. The clear association between clinical signs of disease and dietary supplementation of pups among healthy dogs in a kennel, as well as lack of an obvious pattern of inheritance, suggested an environmentally acquired toxin, specifically the well water. Attempts to reproduce neuropathy in a litter of Beagle pups 2 years after initial evaluation of the disease syndrome were unsuccessful. Atomic absorption studies performed on the well water to detect heavy metals did not reveal toxic concentrations. Toxins that may have been responsible for the neuropathy in these pups were not identified.     

Neosporosis in cats

Six cats (Nos. 1-6) were inoculated intramuscularly with (1 x 10(6)) and orally (5 x 10(5)) tachyzoites of Neospora caninum. Three (Nos. 1-3) of the six cats were given 40 mg/kg methylprednisolone acetate 7 days before and on the day of inoculation with N. caninum tachyzoites, and three cats (Nos. 4-6) were not given methylprednisolone acetate. Two of the cats (cat Nos. 1 and 2) given methylprednisolone acetate died suddenly. Cat No. 1 died 8 days post-inoculation, and cat No. 2 died 16 days post-inoculation. Cat No. 3 was euthanatized 21 days post-inoculation. Cat No. 1 had lesions of gram-positive bacterial septicemia. Necrotizing encephalitis, myelitis, disseminated skeletal muscle necrosis, hepatic necrosis, interstitial pneumonia, and renal tubular necrosis were the main lesions in cat Nos. 2 and 3. The cats that were not given methylprednisolone acetate remained clinically normal except for slight weight loss in cat No. 6. All three of these cats were euthanatized 55 days post-inoculation. Mild myositis and encephalitis were noted on microscopic examination of tissues from these three cats. Neuromuscular lesions were not seen in six control cats (Nos. 7-12) not inoculated with N. caninum and euthanatized 21 or 22 days after administration of the first two doses of methylprednisolone acetate (40 mg/kg), given at a weekly interval.