A serological survey of selected Papua New Guinea blood donors for hepatitis b and related co-infections

Hepatitis B virus (HBV) infection is a serious problem and earlier studies in Papua New Guinea have reported a high prevalence of hepatitis B virus infection. These studies were undertaken using insensitive tests and before an expanded immunization program. The current HBV status is therefore uncertain. A retrospective study to investigate the HBV status was carried out using blood donor data at Nonga General Hospital, East New Britain Province, Papua New Guinea, from January 2003 to December 2018. Additional data for Human Immunodeficiency Virus, syphilis and hepatitis C virus were also collected. Data were analysed using NCSS statistical software. The mean hepatitis B antigen (HBsAg) sero-prevalence was 21% for the period of study and showed a downward trend over the period of the study, which may reflect the effect of the extended immunization program. HBsAg prevalence in male donors (23%) was significantly higher than females (16%). Donors living in Pomio district had a significantly lower proportion of sero-positive HBsAg donors (7%) than Gazelle (22%), Kokopo (22%) and Rabaul (20%), which was attributed to this district's geographical isolation. Ethnically, Pomios donors (8%) had significantly lower HBsAg prevalence than the Taulils, (29%), Bainings (21%) and Tolais (21%). Fifteen to nineteen year olds (23%) were the predominant age group affected, and vertical or perinatal transmission was probably the primary transmission route. Our findings call for greater awareness on the part of public policy makers and should be considered when planning future public health campaigns

Experimentally induced chronic copper toxicity in cattle

Eight Bonsmara bulls and eight Bonsmara heifers, having masses of between 210 and 266 kg when selected, were randomly allocated to four groups, each comprising two bulls and two heifers. Group 1 received 0,6 mg of copper (Cu)/kg of body mass per day (bm/d), group 2, 10 mg of Cu/kg of bm/d and group 3, 20 mg of Cu/kg of bm/d as a copper sulphate solution, given orally, 5 d a week over 745 d. Group 4 was the control group. One bull from group 3 was euthanased on day 679 of the trial, a heifer from group 3 and a bull from group 2, on day 695 of the trial, and a heifer from group 2, on day 731 of the trial, after they had shown clinical signs. During the course of the trial, clinical signs, serum gamma glutamyltransferase and aspartate aminotransferase activity, blood urea nitrogen, and plasma copper, zinc and iron concentrations were monitored. Live mass was recorded weekly to determine any effect on mass gain. The liver and kidney copper, zinc, iron and manganese concentrations at the time of death or slaughter are given. From the results it was concluded that subclinical damage to the liver and eventual copper toxicity can occur when cattle are continually exposed to oral doses ≥12 mg of Cu/kg of bm/d. It was also concluded that cattle can probably tolerate oral doses of ≤0 ,6 mg of Cu/kg of bm/d for an indefinite period, provided there are no other sources of copper, such as may occur with air-pollution, or provided no other adverse mineral interactions occur, such as may occur with molybdenum deficiency.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Palabora Mining Co. Ltd.mn201

Prevalence of trypanosomes and selected symbionts in tsetse species of eastern Zambia

Insect symbionts have attracted attention for their potential use as anti-parasitic gene products in arthropod disease vectors. While tsetse species of the Luangwa valley have been extensively studied, less is known about the prevalence of symbionts and their interactions with the trypanosome parasite. Polymerase chain reaction was used to investigate the presence of Wolbachia and Sodalis bacteria, in tsetse flies infected with trypanosomes (Trypanosoma vivax, Trypanosoma congolense and Trypanosoma brucei). Out of 278 captured tsetse flies in eastern Zambia, 95.3% (n = 265, 95% CI = 92.8–97.8) carried endosymbionts: Wolbachia (79.1%, 95% CI 73.9–83.8) and Sodalis (86.3%, 95% CI 81.7–90.1). Overall, trypanosome prevalence was 25.5% (n = 71, 95% CI = 20.4–30.7), 10.8% (n = 30, 95% CI 7.1–14.4) for T. brucei, 1.4% (n = 4, 95% CI = 0.4–3.6) for both T. congolense and T. vivax, and 0.7% (n = 2, 95% CI 0.1–2.6) for T. b. rhodesiense. Out of 240 tsetse flies that were infected with Sodalis, trypanosome infection was reported in 40 tsetse flies (16.7%, 95% CI = 12.0–21.4) while 37 (16.8%, 95% CI 11.9–21.8) of the 220 Wolbachia infected tsetse flies were infected with trypanosomes. There was 1.3 times likelihood of T. brucei infection to be present when Wolbachia was present and 1.7 likelihood of T. brucei infection when Sodalis was present. Overall findings suggest absence of correlation between the presence of tsetse endosymbionts and tsetse with trypanosome infection. Lastly, the presence of pathogenic trypanosomes in tsetse species examined provided insights into the risk communities face, and the importance of African trypanosomiasis in the area

The conjunctival fungal microflora of horses in a North Queensland tropical environment and their in vitro susceptibilities to antifungal agents

Fungi are ubiquitous in the environment and part of the commensal microflora on the conjunctiva of equine eyes. North Queensland, being tropical, presents an ideal environment for fungi growth. When the cornea is injured, fungi can invade the corneal stroma, resulting in keratomycosis. The objectives of this study were to determine the fungal species specific to the eyes of horses in the Townsville region; to investigate the potential risk factors associated with the presence of fungi; and to test their susceptibility to antifungals to create an empirical guide for treatment. The eyes of forty ophthalmologically normal horses from James Cook University were sampled throughout the summer months of December 2017, January 2018, and January and February 2020. Cultured fungi were identified morphologically, and their identity confirmed by comparing partial 18sRNA DNA sequences with the NCBI nucleotide database. Minimum inhibitory concentration testing of common antifungal medications was performed. Sixty-one out of eighty conjunctival samples grew fungi, and 21 different fungi genera were isolated. The most common genera were Aspergillus (18%, 26/141), Curvularia (14%,20/141), Rhodotorula (12%,17/141) and Penicillium (12%,17/141). No significant association was found between age or environmental factors and fungal culture status. Most fungi were highly susceptible to voriconazole and ketoconazole but resistant to fluconazole and amphotericin B. This adds to the body of evidence on which species of fungi are present as normal ocular microflora of horses living in tropical regions of Australia, and an avenue for treating them

Summer induces DNA damage in boar sperm: implications for the management of seasonal infertility

At 40% share, pork is the most widely eaten meat globally. As such, research efforts must improve production and efficiency in the pig industry to meet growing demand. However, summer heat stress has a significant negative impact on pig fertility; causing embryonic death and decreased litter size that cost the industry millions in productivity losses. This problem is particularly prevalent in the tropics where ambient temperatures rise beyond the animal’s zone of thermal comfort. Boars are particularly vulnerable to the effects of heat stress due to their inefficient capacity to sweat; non-pendulous scrotum; and the high susceptibility of boar sperm to temperature shock. Moreover, due to limited endogenous antioxidant systems inherent in mammalian spermatozoa and the loss of cytosolic repair mechanisms during spermatogenesis, the DNA in these cells are particularly susceptible to oxidative damage. While a seemingly healthy looking sperm may swim and fertilize an oocyte normally, studies in mice demonstrate that heat stress-induced DNA damage can disrupt expression of key developmental genes in early embryos after fertilization and distort the formation of the blastocyst; resulting in implantation failure and pregnancy loss. The aim or our study is to determine whether heat stress induces DNA damage to boar sperm that could significantly contribute to the high rates of embryo loss and pregnancy failure observed in sows during summer infertility. The quality of sperm obtained from n=6 Large White boars housed in the dry tropics of Townsville, North Queensland, Australia was evaluated across different seasons (summer, winter and spring) during 2014 - 2015. Sperm motility was characterised by Computer-Assisted Sperm Analysis (CASA; IVOS version 10: Hamilton Thorne, USA), and sperm DNA integrity evaluated by Terminal deoxynucleotidyl transferase dUTP Nick-End Labelling (TUNEL; In situ cell death detection kit, fluorescein: Roche, Germany). Twenty-thousand spermatozoa per boar per treatment were analysed using flow cytometry (CyAn ADP analyser: Beckman Coulter, USA). Sperm had equal motility across all seasons (total motility: 70.8 ± 5.5% vs. 71.3 ± 8.1% vs. 90.2 ± 4.2%, P ≥ 0.05; progressive motility: 41.7 ± 2.8% vs. 35.4 ± 7.0% vs. 46.6 ± 4.0%, P ≥ 0.05 for spring, summer and winter respectively). However, sperm in summer exhibited ~9-fold higher DNA damage than that in winter and spring (16.1 ± 4.8% vs. 1.1 ± 0.2% and 1.8 ± 0.4% respectively; P ≤ 0.05). These results demonstrate that summer negatively affects sperm DNA integrity in boars without depressing sperm motility. This means traditional methods of evaluating semen quality may not detect inherently compromised spermatozoa. We are currently evaluating the effect of this DNA-damaged sperm on rates of fertilization, development and survival in pig embryos. Our study emphasizes the need for improved management practices and development of strategies to mitigate heat stress in boars during summer

Complete genome sequence of a Newcastle disease genotype XIII virus isolated from indigenous chickens in Zambia

The first complete genome sequence of an African-origin Newcastle disease virus belonging to genotype XIII is described here. The virulent strain chicken/Zambia /Chiwoko/2015 was isolated from diseased chickens in 2015

Cryoprotective effect of glycerol against sperm DNA damage in frozen-thawed boar spermatozoa.

The use of frozen-thawed boar sperm still lags behind chilled boar semen in artificial insemination (AI) operations despite its advantages [1]. Freezing however, may damage the structure and function of sperm, leading to reduced fertilization success. Moreover, glycerol, which is a critical cryoprotectant in most sperm freezing protocols, can be toxic to cells in high concentrations [2]; affecting sperm motility and acrosomal integrity. This study was conducted to determine the cryoprotective effect of glycerol on sperm DNA integrity and motility in frozen-thawed boar sperm

Antioxidant therapy improves sperm DNA integrity in boars during summer

Background: Summer infertility due to heat stress significantly affects the reproductive potential of pigs causing over $300 million per year in lost productivity to the US pig industry and billions worldwide. The boar's inefficient capacity to sweat; non-pendulous scrotum, and the high susceptibility of boar sperm to temperature shock appears to correlate with higher sperm DNA damage during summer. Heat stress-induced sperm DNA damage can result in early embryo loss, as demonstrated in mice. This study investigated whether supplementing boars with antioxidants during summer could improve boar sperm DNA integrity. Method: Motility of sperm obtained from n=5 Large White boars housed in the dry tropics of Townsville, Queensland, Australia were analysed using Computer-Assisted Sperm Analysis. Sperm DNA integrity during summer was compared without or after 42 and 84 days antioxidant supplementation, by Terminal deoxynucleotidyl transferase dUTP Nick-End Labelling and flow cytometry. Paired T-tests were used to determine significant differences between treatments (P ≤ 0.05). Results and Discussion: Total and progressive motility of sperm did not differ between treatments (P ≥ 0.05). However, antioxidant supplementation of boars during summer resulted in a 38% and 55% reduction of DNA-damaged spermatozoa after 42 and 84 days treatment respectively (16.1 ± 4.8% untreated vs 9.9 ± 4.5% vs 7.2 ± 1.6%; P ≤ 0.05). Conclusions: Supplementing boars with antioxidants during summer improves boar sperm DNA integrity which could potentially mitigate the negative impact of heat stress on male fertility. Such improvements may also increase downstream fertilisation rates and early embryo survival in the sow

Antioxidant supplementation alleviates DNA damage in boar spermatozoa induced by tropical heat stress

Seasonal heat stress is known to significantly diminish reproductive performance in pigs, particularly in the tropics, costing the industry millions in annual loses. The boar’s reduced capacity to sweat, non-pendulous scrotum, and widespread use of European breeds in the tropics, makes this species particularly vulnerable to heat stress. While traditionally considered a sow problem, recent mouse studies demonstrate that heat stress-induced sperm DNA damage can result in arrested development and loss of early embryos. Our study investigated the impact of tropical summer heat stress on the quality and DNA integrity of boar sperm, and trialled antioxidant supplementation to alleviate the problem. Data, expressed as mean ± SEM, were analysed by one-way repeated measures ANOVA with pairwise Bonferroni tests. Motility of sperm obtained from n = 5 Large White boars housed in the dry tropics of Townsville, North Queensland, Australia was characterized by Computer-Assisted Sperm Analysis but did not differ between summer, winter or spring (total motility: 71.3 ± 8.1 vs. 90.2 ± 4.2 vs. 70.8 ± 5.5% respectively, P > 0.05; progressive motility: 35.4 ± 7.0 vs. 46.6 ± 4.0 vs. 41.7 ± 2.8% respectively, P > 0.05). Sperm DNA integrity in 20,000 sperm/boar/season, evaluated using TUNEL and flow cytometry, revealed 16-fold more DNA damaged sperm in summer than winter, and nearly 9-fold more than spring (16.1 ± 4.8 vs. 1.0 ± 0.2 vs. 1.9 ± 0.5% respectively, P ≤ 0.05). However, boar feed supplemented with 100g/boar/day of proprietary custom-made antioxidants during summer significantly reduced sperm DNA damage to 9.9 ± 4.5% and 7.2 ± 1.6% (P ≤ 0.05) after 42 and 84 days treatment respectively. Total and progressive motility were not altered by the supplement. In summary, sperm DNA integrity is compromised in boars during summer, suggesting boar factors may contribute to seasonal embryo loss in sows. Moreover, such damage appears undetectable using traditional measures of sperm motility. Antioxidant supplementation during summer appears to mitigate the negative impact of heat stress on sperm DNA integrity