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Vertical transmission in experimentally infected sheep despite previous inoculation with Neospora caninum NcNZ1 isolate

Syed-Hussain SS, Howe L, Pomroy WE, West DM, Hardcastle M, Williamson NB

Vet Parasitol, 2015 Mar 15;208(3-4):150-8.
PMID: 25638717 DOI: 10.1016/j.vetpar.2014.12.036

Recent reports indicate N. caninum has a possible role in causing abortions in sheep in New Zealand. Knowledge about the mode of transmission of neosporosis in sheep in New Zealand is limited. This study aimed to determine the rate of vertical transmission that would occur in lambs born from experimentally inoculated ewes and to determine if previous inoculation would protect the lambs from N. caninum infection. A group of 50 ewes was divided into 2 groups with one group being inoculated with 5×10(6) N. caninum tachyzoites prior to pregnancy in Year 1. In Year 2, each of these groups was subdivided into 2 groups with one from each original group being inoculated with 1×10(7) N. caninum tachyzoites on Day 120 of gestation. Inoculation of N. caninum tachyzoites into ewes prior to mating resulted in no congenital transmission in lambs born in Year 1 but without further inoculation, 7 out of 11 lambs in Year 2 were positive for N. caninum infection. Ewes that were inoculated in both years resulted in all 12 lambs born in Year 2 being positive for N. caninum infection. This indicates that previous inoculation in Year 1 did not result in any vertical transmission in that year but did not provide any protection against vertical transmission in Year 2. These results suggest that vertical transmission occurs readily once the ewe is infected.

Matched MeSH terms: Infectious Disease Transmission, Vertical/veterinary*
Polymerase chain reaction-based discrimination of viable from non-viable Mycoplasma gallisepticum

Tan CG, Ideris A, Omar AR, Yii CP, Kleven SH

Onderstepoort J Vet Res, 2014 09 02;81(1):e1-e7.
PMID: 25686255 DOI: 10.4102/ojvr.v81i1.708

The present study was based on the reverse transcription polymerase chain reaction (RT-PCR) of the 16S ribosomal nucleic acid (rRNA) of Mycoplasma for detection of viable Mycoplasma gallisepticum. To determine the stability of M. gallisepticum 16S rRNA in vitro, three inactivation methods were used and the suspensions were stored at different temperatures. The 16S rRNA of M. gallisepticum was detected up to approximately 20-25 h at 37 °C, 22-25 h at 16 °C, and 23-27 h at 4 °C. The test, therefore, could detect viable or recently dead M. gallisepticum (< 20 h). The RT-PCR method was applied during an in vivo study of drug efficacy under experimental conditions, where commercial broiler-breeder eggs were inoculated with M. gallisepticum into the yolk. Hatched chicks that had been inoculated in ovo were treated with Macrolide 1. The method was then applied in a flock of day 0 chicks with naturally acquired vertical transmission of M. gallisepticum, treated with Macrolide 2. Swabs of the respiratory tract were obtained for PCR and RT-PCR evaluations to determine the viability of M. gallisepticum. This study proved that the combination of both PCR and RT-PCR enables detection and differentiation of viable from non-viable M. gallisepticum.

Matched MeSH terms: Infectious Disease Transmission, Vertical/veterinary
Study on the use of toltrazuril to eliminate Neospora caninum in congenitally infected lambs born from experimentally infected ewes

Syed-Hussain SS, Howe L, Pomroy WE, West DM, Hardcastle M, Williamson NB

Vet Parasitol, 2015 Jun 15;210(3-4):141-4.
PMID: 25935293 DOI: 10.1016/j.vetpar.2015.03.019

To determine if toltrazuril was effective in eliminating Neospora caninum infection from congenitally infected lambs. Twenty-eight ewes were allocated to 3 groups where animals in Groups A and B were inoculated with 1 × 10(7)N. caninum tachyzoites on Day 120 of gestation and Group C was maintained as a negative control group. Lambs born from ewes in Group A were treated with toltrazuril (20mg/kg) on Days 0, 7, 14 and 21 after birth. Lambs in Groups B and C were untreated. All lambs in Groups A and B were seropositive at 12 weeks of age. At 12 weeks of age, no differences between lambs in Group A and Group B were observed in serological results (ELISA and western blot), presence of N. caninum-related brain histopathological lesions or the number of organisms detected by qPCR. Group C remained negative for serology, detection of N. caninum DNA as well as histopathology throughout the study. Results indicate that N. caninum congenitally-infected lambs had a continuing infection with N. caninum despite being treated with toltrazuril.

Matched MeSH terms: Infectious Disease Transmission, Vertical/veterinary*
Fulltext Pathological changes, distribution and detection of Brucella melitensis in foetuses of experimentally-infected does

Mazlan M, Khairani-Bejo S, Hamzah H, Nasruddin NS, Salleh A, Zamri-Saad M

Vet Q, 2021 Dec;41(1):36-49.
PMID: 33349157 DOI: 10.1080/01652176.2020.1867328

BACKGROUND: Brucellosis of goats is caused by Brucella melitensis. It is a re-emerging zoonotic disease in many countries due to transmission from domestic animals and wildlife such as ibex, deer and wild buffaloes.
OBJECTIVE: To describe the pathological changes, identification and distribution of B. melitensis in foetuses of experimentally infected does.
METHODS: Twelve female goats of approximately 90 days pregnant were divided into 4 groups. Group 1 was exposed intra-conjunctival to 100 µL of sterile PBS while goats of Groups 2, 3 and 4 were similarly exposed to 100 µL of an inoculum containing 109 CFU/mL of live B. melitensis. Goats of these groups were killed at 15, 30 and 60 days post-inoculation, respectively. Foetal fluid and tissues were collected for bacterial identification (using direct bacterial culture, PCR and immuno-peroxidase staining) and histopathological examination.
RESULTS: Bilateral intra-conjunctival exposure of pregnant does resulted in in-utero infection of the foetuses. All full-term foetuses of group 4 were either aborted or stillborn, showing petechiations of the skin or absence of hair coat with subcutaneous oedema. The internal organs showed most severe lesions. Immune-peroxidase staining revealed antigen distribution in all organs that became most extensive in group 4. Brucella melitensis was successfully isolated from the stomach content, foetal fluid and various other organs.
CONCLUSION: Vertical transmission of caprine brucellosis was evident causing mild to moderate lesions in different organs. The samples of choice for isolation and identification of B. melitensis are stomach content as well as liver and spleen tissue.

Matched MeSH terms: Infectious Disease Transmission, Vertical/veterinary
Isolation of Neospora caninum from a calf in Malaysia

Cheah TS, Mattsson JG, Zaini M, Sani RA, Jakubek EB, Uggla A, et al.

Vet Parasitol, 2004 Dec 15;126(3):263-9.
PMID: 15567590

In order to attempt isolate the protozoan parasite Neospora caninum, an N. caninum seropositive pregnant Sahiwal Friesian cross heifer from a large-scale dairy farm in Malaysia was kept for observation until parturition at the Veterinary Research Institute, Ipoh. The heifer gave birth to a female calf that was weak, underweight and unable to rise. Precolostral serum from the calf had an N. caninum indirect fluorescent antibody test titre of 1:3200. It died 12 h after birth and necropsy was performed. Brain homogenate from the calf was inoculated into 10 BALB/c mice that were kept for 3 months after which brain tissue from the mice was inoculated onto 24 h fresh monolayer Vero cell lines. The cell cultures were examined daily until growth of intracellular protozoa was observed. DNA of the organisms from the cell cultures was analyzed by PCR and DNA sequencing. DNA fragments of the expected size were amplified from the isolate using N. caninum-specific primers, and sequence analysis of ITS1 clearly identified the isolate as N. caninum. This is the first successful isolation of N. caninum from a bovine in Malaysia, and the isolate is designated Nc-MalB1.

Matched MeSH terms: Infectious Disease Transmission, Vertical/veterinary