First substantiation of clinico-molecular investigation of pathogenic Listeria monocytogenes in Nili-Ravi buffaloes.

Background: Listeriosis is a zoonotic disease of humans, animals, birds, fish, and crustaceans worldwide. Domestic animals, especially ruminants, are more susceptible to listeriosis. This infectious disease is caused by Listeria monocytogenes, an intracellular bacterium that can cross blood-brain, placental and intestinal barriers. In Pakistan, the incidence and reliable diagnostic tools for the L. monocytogenes are unidentified in Nili-Ravi buffaloes. Aims: This study was designed to inspect listeriosis in buffaloes through molecular techniques and haemato-biochemical analyses. Methods: A total of 230 samples (115 milk and 115 faecal samples) were collected from symptomatic listeriosis cases in Nili-Ravi buffaloes of 3 geographical districts (Rawalpindi, Faisalabad, and Muzaffargarh) Punjab, Pakistan. These samples were processed for DNA extraction using commercialized kits, and L. monocytogenes was confirmed by conventional PCR. Results: The results revealed that 6.08% and 4.34% of the isolates from milk and faecal samples were found positive for L. monocytogenes, respectively. The phylogenetic analysis of these isolates showed 97-100% similarity to isolates from the USA, Switzerland, Japan, and India. The accession numbers on NCBI GenBank appeared as HF558398 (Switzerland), KP965732 (India), EU372032 (USA), and LC259850 (Japan). Haemato-biochemical examinations showed that the values of WBCs, plasma fibrinogen, ALT, and AST significantly increased (P<0.05) in diseased buffaloes compared to healthy ones. Conclusion: The occurrence of listeriosis in buffaloes urges continuous monitoring and surveillance to prevent this emerging disease in Pakistan.

Attraction and consumption of methyl eugenol by male Bactrocera umbrosa Fabricius (Diptera: Tephritidae) promotes conspecific sexual communication and mating performance.

The Artocarpus fruit fly, Bactrocera umbrosa (Fabricius) (Diptera: Tephritidae), is an oligophagous fruit pest infesting Moraceae fruits, including jackfruit (Artocarpus heterophyllus Lamarck), a fruit commodity of high value in Malaysia. The scarcity of fundamental biological, physiological and ecological information on this pest, particularly in relation to behavioural response to phytochemical lures, which are instrumental to the success of many area-wide fruit fly control and management programmes, underpins the need for studies on this much-underrated pest. The positive response of B. umbrosa males to methyl eugenol (ME), a highly potent phytochemical lure, which attracts mainly males of many Bactrocera species, was shown to increase with increasing age. As early as 7 days after emergence (DAE), ca. 22% of males had responded to ME and over 50% by 10 DAE, despite no occurrence of matings (i.e. the males were still sexually immature). Male attraction to ME peaked from 10 to 27 DAE, which corresponded with the flies' attainment of sexual maturity. In wind-tunnel assays during the dusk courtship period, ME-fed males exhibited earlier calling activity and attracted a significantly higher percentage of virgin females compared with ME-deprived males. ME-fed males enjoyed a higher mating success than ME-deprived males at 1-day post ME feeding in semi-field assays. ME consumption also promotes aggregation behaviour in B. umbrosa males, as demonstrated in wind-tunnel and semi-field assays. We suggest that ME plays a prominent role in promoting sexual communication and enhancing mating performance of the Artocarpus fruit fly, a finding that is congruent with previous reports on the consequences of ME acquisition by other economically important Bactrocera species.

Effects of estradiol on worm burden and peripheral leukocytes in Parastrongylus malaysiensis-infected rats.

Gonadectomized male laboratory rats were given 0.06 mg/kg estradiol benzoate daily for 14 days before being inoculated with 50 third-stage larvae of Parastrongylus malaysiensis. Hormone treatment was continued until the rats were killed. The numbers of larvae in the brain and of adult worms in the pulmonary area of the rats were determined every 7 days after the inoculation. It was found that the rats treated daily with estradiol benzoate had significantly and consistently higher numbers of larvae and adult worms as compared with the controls. The number of total leukocytes increased significantly after the rats were infected. The results show that estradiol-treated rats become susceptible to P. malaysiensis infection, which may indicate that the immunosuppressive effects of testosterone observed in earlier studies may partly be caused by estradiol that was peripherally aromatized from testosterone.

Worm burden and leukocyte response in Angiostrongylus malaysiensis-infected rats: the influence of testosterone.

Gonadectomized male albino rats aged 7 weeks were given 1.5 mg/kg testosterone propionate daily and inoculated with 50 third-stage larvae of Angiostrongylus malaysiensis. The treatment significantly increased the number of larvae and adult worms recovered from the brain and pulmonary arteries, respectively, and the rats exhibited smaller thymus glands. The total numbers of leukocytes, monocytes, neutrophils, and especially eosinophils increased significantly post-infection, but the counts were higher in the untreated infected controls. Presumably, immunosuppressive effects of testosterone may at least partly be responsible for the higher loads of A. malaysiensis worms found in male rats as compared with females in the field.