Investigations into the prevention of neonatal Ancylostoma caninum infections in puppies by application of moxidectin to the bitch.

The aim of this investigation was to examine whether reactivated Ancylostoma caninum larvae can be eliminated by the administration of moxidectin to pregnant bitches. Four pregnant bitches infected experimentally with 20,000 third-stage larvae of A. caninum were treated subcutaneously with 1 mg moxidectin/kg body weight on day 55 of the pregnancy (5-8 days before parturition). Another four experimentally infected pregnant bitches served as controls. The single moxidectin treatment completely prevented lactogenic infections in the puppies. Neither intestinal stages nor somatic larvae could be found. The administration of moxidectin caused no local or systemic side-effects in the bitches. All 22 puppies of the treated bitches were born healthy and remained so during the whole trial period. Beginning during the third week after birth, all 20 puppies of the untreated bitches developed a severe microcytic, hypochromic anaemia and they revealed a total of 8649 intestinal stages of A. caninum after autopsy.     

Investigations into the prevention of prenatal and lactogenic Toxocara canis infections in puppies by application of moxidectin to the pregnant dog

Aim of the investigation was to examine whether two administrations of moxidectin to pregnant dogs could prevent pre-natal and lactogenic infections of puppies with reactivated Toxocara canis larvae. Four pregnant beagles, infected experimentally with 20 000 embryonated eggs of T. canis, were treated subcutaneously with 1 mg moxidectin per kg body weight on days 40 and 55 of pregnancy (5-13 days before parturition). One further dam and its puppies served as untreated control. Two applications of moxidectin completely prevented pre-natal and lactogenic infections in the puppies. Neither intestinal stages nor somatic larvae were found in the dams or their corresponding puppies. All puppies and dams of the treatment group remained coproscopically negative until 42 days after parturition. The administration of moxidectin did not show any side effects in the dams. None of the puppies of the treated dams showed any pathological abnormalities. In the untreated dam one adult and 26 somatic larvae of T. canis were detected at necropsy. All puppies of the untreated dam showed a patent T. canis infection from day 28 post-natum (p.n.); 296 pre-adult and adult stages of T. canis were spontaneously eliminated and 51 intestinal stages and five somatic larvae of T. canis were recovered at necropsy. In contrast to the puppies of the treated dams all negative control puppies showed blood eosinophilia after parturition and elevated liver enzyme levels.     

Investigations into the prevention of neonatal Ancylostoma caninum infections in puppies by application of imidacloprid 10% plus moxidectin 2.5% topical solution to the pregnant dog

The aim of the investigation was to examine whether a single topical administration of a combination of imidacloprid and moxidectin to pregnant dogs could prevent neonatal infections with reactivated Ancylostoma caninum larvae. Three pregnant beagles, infected with A. caninum, were treated topically with the combination on day 56 of pregnancy. Three further dogs served as untreated controls. Treatment appeared to prevent neonatal infections in the puppies completely. Neither intestinal stages nor somatic larvae were found in two examined puppies per litter. All puppies and dams of the treatment group remained coproscopically negative. No side-effects in dams or puppies were observed. Two of three untreated dams showed a patent infection after parturition. Necropsy of two puppies of each negative control litter revealed seven intestinal and five somatic A. caninum stages in total. One litter of the untreated dams showed a patent infection 33 days after parturition. In the other two litters, no representative sample sizes could be collected.     

The effect of ivermectin on reactivated somatic larva of Ancylostoma caninum Ercolani 1859 (Ancylostomidae) in the pregnant dog

It was evaluated by means of a controlled test to what extent reactivated larvae of Ancylostoma caninum were influenced by single or double treatment with ivermectin. The investigations were done with a total of ten experimentally infected bitches. The single treatment of dams two to ten days ante partum with 0.5 mg or 1 mg ivermectin per kg bodyweight reduced the wormburden of their puppies on an average by 96.6% and 98.5%, respectively. The double treatment with 0.5 mg/kg bodyweight ante and post partum each with an interval of ten days completely prevented lactogenic infections with Ancylostoma caninum. Following a single application of 0.5 mg ivermectin per kg bodyweight the excretion of larvae was markedly delayed and remained on a low level. In addition the infections of the puppies of single treated dams became patent on an average 9.5 and 14.5 days later than the controls. In the bitches no side-effects, neither local nor general, were seen after the treatment with ivermectin. All forty puppies of the treated bitches were born without visible damages.     

Antibody responses in pregnancy-induced transmammary transmission of Ancylostoma caninum hookworm larvae

Third stage larvae of the Ancylostoma caninum hookworm nematode have the capacity to infect a dog, abort the normal maturation pathway to become blood-feeding intestinal worms, and instead distribute throughout the body in a developmentally arrested state that is relatively resilient to most chemotherapeutic agents. During pregnancy, a percentage of the arrested larvae reactivate and transmit via the mammary glands to infect the nursing puppies with resulting iron-deficiency anemia and potential mortality. To determine if the suppression of parasite-specific antibody responses during pregnancy facilitates the reactivation and transmammary transfer of hookworm larvae, a murine model of A. caninum infection was used to compare the infected versus uninfected animals that were either bred or not bred. Initial comparisons of genetically divergent BALB/c versus C57BL/6 mice showed that both the strains mounted strong Th2 biased IgG1and IgE antibody responses to A. caninum infection. Using the BALB/c strain for the breeding analyses, it was confirmed that larval transfer to the mouse pups only occurred during the post-partum lactational period. In the dams, levels of total and antigen-specific IgG1 and total IgE were highly correlated with parasite burden. During most phases of pregnancy and lactation, infected dams had lower total IgG1, IgG2a and IgE levels as compared to unbred mice at comparable times post-infection; this downward modulation of antibody responses supports the established dogma of a generalized immunosuppression associated with pregnancy. However, at parturition and post-partum lactation, antigen-specific IgG1 levels measured at 1 : 5000 serum dilutions were comparable between bred and unbred mice, and antigen-specific IgG2a levels at 1 : 100 serum dilutions were also not significantly different except for a marginal reduction in the bred mice at the lactational timepoint. The comparable anti-A. caninum IgG1 levels between bred and unbred mice, and low correlation between IgG2a levels and larval burden suggest that parasite-specific antibody responses do not play a major role in the pregnancy-associated transmammary transmission of A. caninum larvae. This conclusion does not rule out the possibility that underlying fluxes in the levels of specific cytokines associated with pregnancy and infection may be involved in the process of larval reactivation and transmission.     

Six-month prophylactic efficacy of moxidectin sustained release (SR) injectable for dogs against experimental heartworm infection in growing puppies

The purpose of this study was to assess the efficacy of moxidectin sustained release injectable for dogs (moxidectin SR, Fort Dodge Animal Health) in protecting growing puppies from experimental infection with the heartworm, Dirofilaria immitis, six months after treatment. The study involved 27 puppies, approximately 12 weeks of age at the beginning of the study, with nine puppies in each of three size classes. The small breed class included eight Pekingese and one purpose-bred small breed mongrel; the medium breed class included nine purpose-bred mongrels, and the large breed class included nine puppies with an anticipated adult weight >or=30-35 kg. Both genders were included with no attempt made to have equal numbers of male and female puppies. Puppies were blocked by weight within each size class and randomly assigned to three treatment groups of nine dogs. On Day 0, pups in two groups were injected subcutaneously with moxidectin SR, dosed to deliver 0.17 mg moxidectin/kg b.w. The third group was injected with sterile saline. Personnel making observations were blinded to the treatment status of the animals. Following treatment, puppies were observed for signs of adverse local and systemic reactions. Puppy weights and serum moxidectin levels were also monitored. On Day 180, puppies in all treatment groups were inoculated subcutaneously with 50 third-stage larvae of D. immitis. On Days 348 and 349, puppies were euthanatized and necropsied. Hearts and lungs were examined for adult heartworms. All animals in the saline control group were infected with an arithmetic mean of 39.22 adult heartworms each. Seventeen of 18 dogs in the moxidectin SR-treated groups were uninfected. One treated puppy was infected with a single adult heartworm. This infected individual was from the large breed size class and had the second highest percent increase in body weight. Based on arithmetic means, the heartworm recovery from all treated puppies represents a 99.86% reduction relative to the saline control. There were no adverse local or systemic reactions to treatment in any animal.     

Prenatal and transmammary infections of Toxocara canis in dogs: effect of benzimidazole-carbamate anthelmintics on various developmental stages of the parasite

Fenbendazole and albendazole, given at a dose rate of 150 mg/kg for 3 days, produced a 90 per cent reduction in the numbers of second stage larvae of Toxocara canis present in the tissues of dogs although no reduction in the number of larvae found in the brains of infected dogs occurred with this treatment. The results suggest that a course of 3 day therapy with these anthelmintics should prevent prenatal infections in puppies. However, if infection is acquired by bitches during late pregnancy or early lactation, the transmammary route of infection becomes important. Therefore, anthelmintic treatment of the bitch prior to pregnancy will not prevent transmission of infection to her puppies should the bitch acquire a new infection of T. canis during pregnancy or early lactation. Alternatively, infection with T. canis can be controlled through the treatment of neonatal puppies for migrating larvae of T. canis. Treatment of newborn puppies with fenbendazole, albendazole or oxfendazole at a dose of 100 mg/kg for 2–3 days produced a 91–99 per cent reduction in the number of adult parasites found. In addition, a single dose of fenbendazole, given at a dose rate of 40 mg/kg, eliminated 93–96 per cent of adult T. canis from the intestines of 4–5-week-old puppies. These latter treatments would need to be repeated to eliminate completely the infection from puppies.     

Molecular assessment of the transplacental transmission of Toxoplasma gondii,Neospora caninum,Brucella canis and Ehrlichia canis in dogs

Given the fact that numerous microbial species can be detected in pregnant female dogs, the objective of this study was to assess the transplacental transmission of Brucella canis, Ehrlichia canis, Neospora caninum and Toxoplasma gondii in stillborn puppies. This study involved 41 stillborn puppies, 78.6% of which were positive for T. gondii, 52.4% for N. caninum and 59.5% for B. canis. E. canis was not detected in any of the analyzed puppies. Pregnancy is an important physiological condition for the transmission of infectious agents to puppies and transplacental transmission may be epidemiologically relevant in the spread of these opportunistic agents.     

Clinical Evaluation of the Use of Aglepristone Associated with Oxytocin to Induce Parturition in Bitch

To evaluate the efficacy and safety of aglepristone 15 mg kg⁻¹ for induction of parturition in bitches, 22 pregnant beagle bitches were injected subcutaneously on day 60 post-estimated LH surge, and again 24 h later with aglepristone and subsequently were given 0.15 IU kg⁻¹ oxytocin at hourly intervals until delivery of the last puppy. Six pregnant beagle bitches were used as a non-treated control group. In the control group, parturition occurred at 63.2 ± 0.5 days, 29 pups were born and the average expulsion time per puppy was 1.0 ± 0.6 h. In the treated group, parturition was obtained on average 29.7 ± 5.6 h after aglepristone administration, 121 pups were born and average expulsion time per pup was 1.1 ± 0.4 h. The percentage of live puppies, 7 weeks after birth, was 86.1% (25/29) and 86.8% (105/121) for the control and treated groups, respectively. No significant difference was observed between the control and treated groups for the average expulsion time per live puppy and for the percentage of live puppies at birth, 48 h, 7 days or 7 weeks after birth (p > 0.05). This study confirms previous results and demonstrates that the combination of aglépristone and oxytocin can be safely and reliably used to induce parturition in beagle bitches, at 60 days post-estimated LH surge.     

Colonization of neonatal puppies by staphylococci.

The composition of the normal staphylococcal flora of bitches and their litters held in a breeding unit was studied. The animals were sampled at a number of sites using moistened swabs. Six bitches were sampled daily, for 10 days, before whelping and then, together with four puppies per litter, at whelping (day 11) and at 1 and 7 days thereafter. Staphylococcus intermedius formed the predominant staphylococcal isolate. S. intermedius counts at the oral and nasal sites on the bitches did not change markedly before whelping and remained low (< 6 cfu/swab). Significant rises in the oral counts on both the bitches (P < 0.05) and puppies (P < 0.001) were then observed after whelping (days 11-18). Abdominal counts on both the bitches and puppies also rose (P < 0.001) after whelping. S. intermedius counts at the vaginal vestibulum of the pregnant bitches were found to be higher than at any other site sampled and did not alter markedly until whelping when a decrease (P = 0.05; days 10-12) was observed. S. intermedius was not found at the anal site in any of the six bitches and only transiently colonized five of the puppies.     

Parasitologic, clinical, hematologic and serologic findings in puppies after lactogenic infection with Ancylostoma caninum ERCOLANI 1859 (Ancylostomidae)]

The correlation between intensity of Ancylostoma caninum infections in bitches and the intensity of lactogenic infections and clinical signs of their puppies was investigated. On average, 825, 1,867 or 2,125 specimens were observed in litters of two bitches inoculated with 5,000, 10,000 or 20,000 third stage larvae (LIII) respectively, at the day of conception. Adverse effects of the infection on the growth and behaviour of the puppies were observed after onset of their second week of life: 11/27 puppies died during the fourth week. The body weight of puppies surviving 28 days was up to 750 g less than that of uninfected controls. Eosinophilia, erythroblastosis and microcytic, hypochromic anemia developed in all puppies during their first four weeks. The IFA test (LIII antigen) was positive for only 5/18 heavily infected puppies after uptake of colostrum.     

Bacteriological Status of Canine Milk and Septicaemia in Neonatal Puppies – a Retrospective Study

Results of the bacteriological examination of milk samples from 46 bitches were evaluated retrospectively, and correlated with findings of the bacteriological examination of organs from dead, septicaemic puppies in their litters (n = 33). The aim of this study was to investigate, in how many cases of clinical and subclinical mastitis of the bitches, the same bacteria can be detected in their septicaemic neonates. One group of lactating bitches was clinically healthy (group I, n = 38), whereas in eight bitches different puerperal disorders were found (group II). Twenty‐five septicaemic puppies were from group I, eight from group II. Out of a broad spectrum of bacteria isolated from the milk of clinically healthy and diseased bitches, only Escherichia coli, Klebsiella pneumoniae and/or ß‐haemolytic (haem.) Streptococcus sp. could be isolated from organs of their septicaemic puppies. This was the case in three bitches with mastitis and in one clinically healthy bitch only. Staphylococcus intermedius, although frequently isolated from canine milk, does not seem to be a cause of septicaemia in neonates. It is assumed that in most cases of neonate septicaemia, bacteria from the bitches’ milk are not the primary cause.     

The serological response of young dogs to the Flury LEP strain of rabies virus vaccine

The serological response of puppies from Nigeria to live Flury low egg passage (LEP) rabies vaccine was determined. Two sets of puppies were used: one set from rabies-vaccinated bitches and another set from non-vaccinated bitches. Puppies were vaccinated intramuscularly with Flury LEP strain rabies vaccine and serially bled from the 4th week to the 30th week. Serum rabies virus neutralizing antibodies (VNA) were measured by a modified rapid fluorescent focus inhibition test (RFFIT). Puppies from non-vaccinated bitches responded well to vaccination after the 4th week and through to the 10th week of age, showing a progressive increase in VNA. In contrast, puppies from vaccinated bitches responded well to rabies vaccination only at 10 weeks of age, although detectable maternal rabies VNA and rabies anti-ribonucleoprotein (RNP) antibodies had decreased by 6 weeks post partum.     

Transmission of Babesia spp by the cattle tick (Boophilus microplus) to cattle treated with injectable or pour-on formulations of ivermectin and moxidectin

OBJECTIVE: To assess the efficacy of ivermectin and moxidectin to prevent transmission of Babesia bovis and Babesia bigemina by Boophilus microplus to cattle under conditions of relatively intense experimental challenge. DESIGN: Naive Bos taurus calves were treated with either pour-on or injectable formulations of either ivermectin or moxidectin and then exposed to larvae of B microplus infected with B bovis or larvae or adults of B microplus infected with B bigemina. One calf was used for each combination of haemoparasite, B microplus life stage, drug and application route. PROCEDURE: Groups of calves were treated with the test drugs in either pour-on or injectable formulation and then infested with B microplus larvae infected with B bovis or B bigemina. B bigemina infected adult male ticks grown on an untreated calf were later transferred to a fourth group of animals. Infections were monitored via peripheral blood smears to determine haemoparasite transmission. RESULTS: Cattle treated with either pour-on or injectable formulations of ivermectin and moxidectin became infected with B bovis after infestation with infected larvae. Similarly, larvae infected with B bigemina survived to the nymphal stage to transmit the haemoparasite to animals treated with each drug preparation. Cattle treated with pour-on formulations of ivermectin and moxidectin then infested with adult male ticks infected with B bigemina did not become infected with B bigemina whereas those treated with the injectable formulations of ivermectin and moxidectin did show a parasitaemia. CONCLUSIONS: Injectable or pour-on formulations of ivermectin and moxidectin do not prevent transmission of Babesia to cattle by B microplus. Use of these drugs can therefore not be recommended as a primary means of protecting susceptible cattle from the risk of Babesia infection.     

Evaluating the accuracy of canine pregnancy diagnosis and litter size using real-time ultrasound

A total of 135 bitches suspected of being pregnant were examined with a real-time ultrasound equipment. 58 bitches were not pregnant. In pregnancy diagnosis ultrasound produced an overall accuracy of 99.3%, sensitivity 98.7%, and specificity 100.0%. Estimation of the litter size was fairly reliable in small litters of 1–3 puppies.     

Toxocara canis infection induces antigen-specific IL-10 and IFNgamma production in pregnant dogs and their puppies

Toxocara canis (T. canis) is originally a parasite of canine bitches and their pups. The pathogenicity of T. canis infection is enhanced during pregnancy and puppyhood. The aim of this study was to investigate if modification of IFNgamma and IL-10 secretion occurs during infection in pregnant dogs and puppies. Analysis of cytokines secreted could let us hypothesize a role for IL-10 and/or IFNgamma in T. canis infection. We tested T. canis-specific production of IFNgamma and IL-10 by lymphocytes of pregnant dogs and their puppies after in vitro re-exposure to purified excretory/secretory antigen (ESAg) from T. canis. Blood mononuclear cells (BMC) isolated from pregnant dogs and their puppies were cultured in the presence of ESAg. Cultures' supernatants were tested for cytokine levels by ELISA. Results obtained showed that IL-10 concentrations increased during pregnancy in infected animals and in the meantime IFNgamma production decreased. In puppyhood, we observed that, IL-10 concentration decreased with the age of puppies mainly in infected animals while IFNgamma increased. In conclusion, our data suggests that BMC of infected dogs have a particular modification of IL-10 and IFNgamma synthesis. These data could be the basis to design immunotherapeutic approaches.     

Efficacy of moxidectin against gastrointestinal nematodes of cattle.

Three groups of 11 naturally infected crossbred beef calves were injected subcutaneously with moxidectin 1 per cent injectable at 0.2 or 0.3 mg moxidectin/kg bodyweight or with the unmedicated vehicle. Nematode infections had been acquired during grazing from December to April. Based on the faecal egg counts and total worm counts of the control calves at necropsy (11 to 13 days after treatment) most of the calves had heavy parasitic burdens. Ostertagia ostertagi was predominant and the mean numbers of adults, developing fourth stage larvae (L4) and inhibited early L4 were 45,906, 10,061 and 68,918, respectively. Haemonchus placei and Trichostrongylus axei were also present in the abomasa. Three species of Cooperia, Oesophagostomum radiatum L4 and T colubriformis adults were found in the intestinal tract. Both dosages of moxidectin were equally effective (P < 0.05) against all the abomasal nematodes (99.9 to 100 per cent) and the intestinal tract nematodes (99.4 to 100 per cent). No adverse reactions to the moxidectin treatment were observed. Abomasal pathology characteristic of heavy O ostertagi infection was observed in the control calves, but not in the treated calves.     

Imidacloprid/moxidectin topical solution for the prevention of heartworm disease and the treatment and control of flea and intestinal nematodes of cats

Sixteen controlled laboratory studies, involving 420 kittens and cats, were conducted to evaluate the efficacy and safety of topically applied formulations of imidacloprid and moxidectin for the prevention of feline heartworm disease, treatment of flea infestations and treatment and control of intestinal nematodes. Unit-dose applicators and the dosing schedule used in these studies were designed to provide a minimum of 10mg imidacloprid and 1mg moxidectin/kg. Treatments were applied topically by parting the hair at the base of the skull and applying the solution on the skin. Imidacloprid treatment alone did not display activity against Dirofilaria immitis or intestinal nematodes and moxidectin treatment alone provided little or no activity against adult Ctenocephalides felis infestations. The formulation containing 10% imidacloprid and 1% moxidectin was 100% efficacious against the development of adult D. immitis infections when cats were treated 30 days after inoculation with third-stage larvae. A single treatment with this formulation also provided 88.4-100% control of adult C. felis for 35 days. Imidacloprid/moxidectin was 100% efficacious against adult Toxocara cati and 91.0-98.3% efficacious against immature adults and fourth-stage T. cati larvae. The formulation provided 98.8-100% efficacy against adult Ancylostoma and immature adults and third-stage A. tubaeforme larvae. Monthly topical application with 10% imidacloprid/1% moxidectin is convenient, efficacious and safe for the prevention of feline heartworm disease, treatment of flea infestation and for the treatment and control of intestinal nematode infections of cats.     

Foetal pulmonary maturity in dogs: Estimated from bubble tests in amniotic fluid obtained via amniocentesis

The goal of this study was to evaluate the reliability of amniocentesis during late pregnancy to assess lung maturity in puppies using a bubble test as described by Gunston and Davey (South African Medical Journal, 54, 1978, 495). Thirty‐five bitches from eight different breeds were followed during late pregnancy before undergoing elective Caesarean (C)‐section on days 61–62 after ovulation. Bubble tests were performed the day before the C‐section (n = 11 bitches) and before the administration of aglepristone on amniotic fluid samples obtained via amniocentesis and were repeated the day of the surgery on amniotic fluid samples collected via puncture of the amniotic bags before they were opened (n = 35 bitches). No complications were observed following amniocenteses and the C‐sections. The mortality rate (2.3%) was similar to the result of other studies using the same protocol for an elective C‐section. Of the non‐contaminated samples collected the day of the C‐section, 89.6% were positive in the bubble test, which was consistent with observations of clinical maturity the day of the surgery and on the following days. In contrast, 70% of the samples collected the day before the C‐section (when progesterone concentrations were still high) were negative, suggesting that the puppies were still immature at this point in the pregnancy. Additionally, we observed a significant difference in the bubble test results before and 18 hr after the administration of aglepristone, suggesting that aglepristone may act as an inducer of the final maturation of the puppies by inactivating progesterone receptors and simulating a physiological decrease in progesterone. Finally, we confirmed the need to exclude all contaminated samples, which could lead to false‐negative results.     

A retrospective study of female reproductive parameters in the Kunming dog

The Kunming dog is the first and only working dog breed from China to be recognized worldwide. As a domestic working dog, its excellent working performance has been well established; however, its normal reproductive parameters are not well understood. Therefore, this study was conducted to document the main reproductive parameters of this purebred working dog in field breeding conditions. Data on 1004 heats (753 with mating) from 203 bitches between 2008 to 2014, were collected and analyzed. The pregnancy rate and whelping rate was 79.42% and 75.30%, respectively. Finally, for 567 litters (4298 puppies), the mean litter size was 7.19 ± 0.12 puppies (range 1–15). The mean gestation period and birth weight were approximately 61.64 ± 0.10 days and 407.25 ± 1.21 g. The mean sex ratio was 1.03 males to 1.00 female. Estrus occurred throughout the year with no significant differences between seasons and months (P > 0.05), which confirms that Kunming dogs are non‐seasonal breeders; births occurred in every month of the year. Pregnant bitches exhibited significantly longer inter‐estrus intervals than non‐pregnant bitches (220.85 ± 2.05 vs. 180.19 ± 2.94 days, P < 0.05). Bitch parity influenced litter size, and the gestation length and birth weight of the puppies were negatively affected by litter size. This study helps elucidate the reproductive potential of this breed and provides reference values for reproductive performance in the Kunming dog.