The optimum distance and duration of ultraviolet (UV) irradiation for the complete inactivation of African catfish Clarias gariepinus egg nucleus was investigated in this study. The UV light was suspended above the unfertilized eggs at four distances (5, 10, 20 and 30 cm) and for five durations (1, 2, 3, 4 and 5 min). Then, the irradiated eggs were activated with sperm from diploid C. gariepinus and cold shocked at 5°C for 5 min just moments before cell cleavage. Ploidy analysis was performed using karyotype chromosome counting. The results obtained suggested that the further the distance, the better the hatchability rate, however prolonged duration seemed to significantly reduced hatchability. All treatments with surviving progenies at the end of the study showed evidence of successfully diploid gynogen (2n = 56) induction at different percentages. However, the optimal protocol that gave a moderately high hatchability/survival rate and completely induced gynogens was exposure of the eggs to UV irradiation at 20 cm for 1 min. It was concluded that the distance and duration of UV irradiation affects gynogenetic induction in African catfish C. gariepinus.
SummaryThis study investigated the breeding parameters and embryogenic development of diploid and heat shock-induced triploid eggs of Anabas testudineus (Bloch, 1792). To this effect, broodstocks of A. testudineus were induced to spawn using the Ovaprim® hormone. After fertilization, the eggs were divided into two groups and one portion heat shocked at 41°C (for 3 min), at approximately 4 min after fertilization. Results of fertilization, hatchability, as well as the sequence and timing of embryogenic development were collated from three breeding trials. Fertilization percentages were similar in both treatments (≈90%) while hatchability was higher in the diploid eggs (79.56%) than the triploid induced eggs (50.04%). Both treatments had the same sequence of embryogenetic stages; however, the timing of development was significantly delayed in the triploids (i.e. beyond the 2-cell stages) as compared with the observations in the control group (diploid eggs). Consequently, hatching time was 5 h faster in the diploid eggs [i.e. 18 hours post fertilization (hpf)] compared with the triploid induced eggs (23 hpf). The most critical stage of embryonic development in which mass mortality occurred in the different treatments was the somite stage. The status of triploid hatchlings was affirmed using erythrocyte morphology in 2-month-old fingerlings.
Leiomyosarcoma of the scrotum is a rare tumor. Johnson H Jr in 1987 reported first case. Only 39 cases been reported in the literature. A 74 years old Indian gentleman presented with progressive painless right testicular swelling for 3 months. On examination, a firm right testicular mass. We proceeded with right scrotal exploration with excision of the right scrotal mass. Histopathology showed scrotum leiomyosarcoma. We would like to discuss the rarity of presentation, dilemma of diagnosis and managing in a district hospital. We advocate wide local excision with clear margin of 2 cm which give good overall survival benefits.
Fibrosarcoma is rare in the pediatric age group. It generally involves the extremities and the trunk but rarely involves the genital area. We report a case of a large fungating infantile fibrosarcoma of the penis in a 2-year-old Malay boy. Partial recovery of the penile structure was achieved after chemotherapy. The difficulty in managing the social and surgical aspect of this case is discussed in our report. To the best of our knowledge, this is the first case report of infantile fibrosarcoma involving the penis in an Asian region.
Human metapneumovirus (HMPV) is a recently discovered cause of viral respiratory infections. We describe clinical and molecular epidemiology of HMPV cases diagnosed in children with respiratory infection at University of Malaya Medical Centre, Kuala Lumpur, Malaysia. The prevalence rate of HMPV between 2010 and 2012 was 1.1%, and HMPV contributed 6.5% of confirmed viral respiratory infections. The HMPV patients had a median age of 1.6 years, and a median hospital admission of 4 days. The most common clinical presentations were fever, rhinitis, pneumonia, vomiting/diarrhoea, and bronchiolitis. Based on the partial sequences of F fusion gene from 26 HMPV strains, 14 (54%) were subgenotype A2b, which was predominant in 2010; 11 (42%) were subgenotype B1, which was predominant in 2012; and 1 (4%) was subgenotype A2a. Knowledge of the circulating subgenotypes in Malaysia, and the displacement of predominant subgenotypes within 3 years, is useful data for future vaccine planning.
Intestinal parasitic infections are among the most common diseases affecting mankind causing major public health problems to billions of people living in developing countries. The aim of this study is to determine the prevalence of intestinal parasites in various communities residing in different habitats in Malaysia and compare the findings with 101 studies conducted over the past 42 years (1970-2013). A cross-sectional study design was conducted with the aid of a questionnaire to collect relevant information about the study population. Faecal samples were examined using the direct smear and formal ether sedimentation techniques. A total of 342 children were examined amongst whom 24.6% were positive for intestinal parasitic infections. Results showed that 32.3% of rural children, 20.6% of urban squatters and 5.4% of children from flats were positive for one or more parasites. The most common parasite encountered was Trichuris trichiura (20.2%) followed by Ascaris lumbricoides (10.5%) and hookworm (6.7%). No case of hookworm was reported in urban children whereas 12.2% of rural children were positive. The most common protozoan parasite detected was Entamoeba coli (3.2%) followed by Giardia intestinalis (1.8%), Entamoeba histolytica (1.8%) and Blastocystis hominis (1.2%). Nearly one-fifth (18.4%) of the children had single infection followed by double (12.0%) and triple infections (1.2%). Orang Asli (indigenous) children (44.3%) had the highest infection rate followed by Indians (20.2%), Malays (14.0%) and Chinese (11.9%). Twenty-eight studies carried out on plantation communities with regards to intestinal parasitic infections in Malaysia from 1970 to 2013 showed a steady decline in the prevalence rate ranging from 95.0% in the seventies to 37.0 % in 2012. Intestinal parasitic infections were more common in Orang Asli communities with prevalence ranging from over 90% in the seventies and fluctuating below 70% in most studies between 2000 to 2013 except for two studies that showed a prevalence of 98.2% and 100%. The prevalence rate among urban squatters, urban residents and those living in flats showed dramatic decrease in prevalence rate.
This study was conducted to determine the prevalence of intestinal parasites among children and adult Orang Aslis (Aborigines) from different locations in Perak. Faecal samples were collected and analyzed using the direct smear and formal ether sedimentation technique. Some of the faecal samples were stained using the Modified Acid fast stain for Cryptosporidium. Nail clippings of the respondents and the soil around their habitat were also analyzed. Of the 77 stool samples examined, 39 (50.6%) were positive for at least one intestinal parasite. The most common parasite detected was Trichuris trichiura (39.0%) followed by Ascaris lumbricoides (26.9%), Entamoeba coli (5.2%), Giardia lamblia (5.2%), Blastocystis hominis (3.9%), hookworm (3.9%), Entamoeba histolytica (1.3%), Iodamoeba butschlii (1.3%) and Cryptosporidium sp. (1.3%) respectively. Some respondents had single parasites (24.7%), some with two parasites (18.2%). Some with three parasites (6.5%) and one had four parasites species (1.3%). The parasites were slightly more common in females (54.7%) than males ((41.7%). The parasites were more common in the 13-20 year age group (90.9%) followed by 1-12 years (69.6%), 21-40 year age group (34.8%) and least in the 41-60 year age group (27.8%). Nail examinations of the respondents did not show any evidence of parasites. One had a mite, three had pollen grains and one had yeast cells isolated from the finger nails. Soil samples taken around their houses showed only one sample with a nematode ova and one with oocyst which was of a non human origin.
A burned human remain was found outdoor (5º 27' N, 100º 16' E) in Penang Island. The deceased was last seen alive on 23 April 2010 at 2230 h and was found burned on 24 April 2010 at 1920 h. Larval aggregation of second instar Chrysomya megacephala was observed on the chest of the deceased.
The life history of the male and female of the indoor forensic fly, Synthesiomyia nudiseta was studied under fluctuating temperature of indoor environments and analysed based on the age-stage and two sex life table. The life cycle of S. nudiseta was 14.0±1.0 days from the egg stage to adult emergence. The population parameters calculated were; net reproduction rate (R(o)= 108.6), mean generation time (T(o)= 12.2), intrinsic rate of increase (r(m)= 0.38), and finite rate of increase (λ= 1.46). The pre-oviposition period (APOP) was 6.0± 0.1 days. All population parameters suggested that S. nudiseta exhibits the r-strategist characteristics.
Two performance (efficacy and attractiveness) comparisons of neonicotinoid baits QuickBayt® (imidacloprid) and Agita® (thiamethoxam) against filth flies were conducted under field conditions to determine suitability for use outdoors. The first experiment compared bait performance and the second compared effects of different applications on QuickBayt® performance. Applications compared were: (i) scattered in petri dish (SPD); (ii) wet-down in petri dish (WPD); (iii) scattered on cardboard (SCB) and (iv) painted on cardboards (PCB). Efficacy and attractiveness were assessed based on knockdown percentage (KD%) and number of flies feeding on baits, respectively. The KD% of QuickBayt® (34% ± 3.0%) was not significantly higher than Agita® (29% ± 1.3%) (t-test, P>0.05). Agita® (101 ± 5.7 flies) was significantly more attractive to flies than QuickBayt® (76 ± 4.8 flies) and the sugar solution (49 ± 7.2) (one-way ANOVA, P<0.05). The PCB and SCB applications were significantly more attractive to filth flies than WPD and SPD (One-way ANOVA, P<0.05), however differences in KD% were not significantly different (One-way ANOVA, P>0.05). The two baits provided the same level of efficacy in a wide-open area against filth flies of various species. QuickBayt® was more versatile; efficacy was not significantly affected by different applications. Surface area and moisture affects attractiveness of the bait.
Japanese encephalitis (JE) virus activity is an important cause of viral encephalitis in Southeast Asia. In Malaysia, JEV activity has been first detected in Culex gelidus in 1976. Since then, no study has fully addressed the seasonal dynamics of this mosquito. As irrigated rice production expands, the incidence of JEV vectors, particularly Cx. gelidus is expected to increase. We surveyed Penang Island to determine the breeding patterns of Cx. gelidus and their potential insect predators, in relation to habitat/niche and rice growing period. Six rice fields proper (RFP) and related drainage canals (DC) were visited through three cultivation cycles (CCs) over 17 months. Weekly visits were performed to each of the 36 sites and mosquito larvae and aquatic insects were sampled from RFP and DCs using dippers. Culex gelidus was abundant in RFP and almost absent in DCs. Its densities usually were high during the first and 3rd CC and when the RFs were in Fp, Pp and Gp. In DCs, the mosquito was abundant during Mp, e.g., 2nd CC. Predators, especially those belonging to the families Corixidae, Coenagrionidae and Dytiscidae, were more present in RFP. Predator numbers usually were high during the first CC; in some cases predator abundance peaked during other CCs, e.g., corixids and dysticids. In RFP, neither corixids nor coenagrionids showed any positive correlation with densities of Cx. gelidus. However, dytiscids' population peaked when the mosquito densities were on the rise. These observations suggest that Cx. gelidus is active during the period of rice cultivation. Operational vector control through bio-control or with insecticides near the end of the rice cultivation season in RFP may prove beneficial in reducing the density of Cx. gelidus, but also the amount of bio-agent or insecticide applied on riceland.
The pupae of Desmometopa sp. (Diptera: Milichiidae) were collected from a human corpse found indoor in active decay stage together with the larvae of Sarcophagidae, Synthesiomyia nudiseta (Wulp), Chrysomya megacephala (Fabricius) and Chrysomya rufifacies (Macquart). This research note is the first report of the Desmometopa sp. recovered from a human corpse in Malaysia.
A human corpse at an advanced stage of decomposition was found in a house in the residential area of Bukit Mertajam, Penang, Malaysia. Entomological specimens were collected during the post-mortem and the live specimens were subsequently reared at room temperature. The time of death was estimated to have been 14 days previous to the discovery of the body based on the police investigation. Both adult and larvae of the beetle Dermestes ater (De Geer) were found to be infesting the corpse and from the stage of decomposition of the body and the estimated time of death it would appear that infestation may have begun at a relatively early stage of decomposition.
This study was carried out in an oil palm plantation in Bandar Baharu, Kedah using monkey carcasses and focuses in documenting the decomposition and dipteran colonization sequences in 50 days. This is the first study of Diptera associated with the exploitation of carcasses conducted in the north of peninsular Malaysia during the dry and wet seasons thereat. During the process of decomposition in both seasons, five phases of decay were recognized namely fresh, bloated, active decay, advance decay and dry remain. In this decomposition study, biomass loss of carcass occurred rapidly during the fresh to active decay stage due to the colonization and feeding activity of the Diptera larvae. The duration of the fresh and bloated stages of decay were the same in wet and dry seasons but later stages of decay were markedly shorter during the wet season. Twenty one species of adult Diptera were identified colonizing carcasses in the study period. Among the flies from the family Calliphoridae, Chrysomya megacephala Fabricius and Chrysomya nigripes Aubertin were recognized as the earliest arrivals on the first day of exposure. Adult Ch. nigripes was abundant for approximately two weeks after placement of the carcasses. By comparing the percentages of adults collected during the study period, the calliphorids abundance in percentages in wet season was 50.83%, but in dry season, the abundance was only about 35.2%. In contrast, the percentage of Sphaeroceridae in wet season was only 3.33%, but in the dry season, the abundance was 20.8%. Dipteran in family Phoridae, Piophilidae, Sepsidae, Drosophilidae and Dolichopodidae colonized the carcasses for a long period of time and were categorized as long term colonizers.
Larvae of the Synthesiomyia nudiseta (Wulp) were collected from a decomposed human corpse at the Department of Forensic Medicine, Penang Hospital. A colony of this species was established and the eggs were collected for rearing. The developmental times, rearing temperatures, and relative humidity were recorded twice daily from the time the eggs collected until adult emergence. An average of 5 larvae were randomly collected from the rearings twice daily, warm-water killed and preserved in Kahle's solution. The larval instar stages were determined by observing the number of posterior spiracular slits and the length of the preserved larvae were measured. When the larval life cycle was completed, the accumulated developmental times were calculated. A total of 8 replicates were carried out. The temperature of the rearing room was 28.5+/-1.5 degrees Celcius while the relative humidity was within 67-85%. The total developmental time for S. nudiseta was 322+/-19 hours (13.4+/-0.8 days).
Three species composition surveys were conducted in a rural location in Kedah and an urban location in Pulau Pinang. Two of the surveys were conducted in November 2003, the first was at the Kedah site and the second was at the Pulau Pinang site. The third survey was conducted at the Pulau Pinang site again on the last week of April 2004. All these surveys were conducted one week prior to field evaluations of commercial chemical fly baits. The predominant species recovered from the surveys was the house fly, Musca domestica, which ranked first in prevalence in all three studies. Catches of Musca sorbens, Chrysoma megacephala and Lucillia cuprina were lower than M. domestica. Sarcophaga sp. was not present at the Kedah site and was only present at the Pulau Pinang site during the survey in April 2004. The other fly species present at the Kedah site were Megaselia sp., Psycoda sp., Piophila sp. and Fannia sp. These species were scarce and never exceeded 1% of the total catch.
The efficacy and residual efficacy of commercial baits, Quick Bayt (0.5% w/w imidacloprid) and Agita (10.0% w/w thiamethoxam) against synanthropic flies were evaluated under field conditions. Efficacy was evaluated based on knockdown percentage (KD %). The bait efficacy and residual efficacy evaluation were conducted for a period of 3 weeks and 6 weeks respectively. Baits were applied onto bait targets and placed on fly-count targets to facilitate the counting of flies. All baits were applied according to the manufacturer's recommended application rate. Three replicate treatments for each type of bait were placed at the study site each week. The number of flies feeding on baits and the knocked down flies were counted and collected. The efficacy of Agita and Quick Bayt did not differ significantly (t-test, P>0.05) over the 3-week period, even though Quick Bayt had a slightly higher KD% than Agita. In the residual efficacy evaluation, the (knockdown) KD% of Quick Bayt was consistent at around 36% for the first five weeks but dropped to 33.8 +/- 0.4% on the sixth week. The KD% for Agita on the first week was 33.6 +/- 12.2% and remained relatively consistent for the first 4 weeks at around 31%. KD% dropped to 16.7 +/- 3.3% on week 5 and to 15.7 +/- 1.2% on week 6. The difference in residual efficacy of the two baits was significant (t-test, p < 0.05).
A semi laboratory experiment using 3 cohorts of Aedes albopictus adults was performed to obtain age-specific mortality and fecundity information and to derive statistical estimates of some population growth parameters. Life expectancy was calculated for both males and females. The following population parameters were estimated: intrinsic rate of increase (rm= 0.21), net reproductive (replacement) rate (Ro= 68.70), age at mean cohort reproduction (To=10.55 days), birth rate (B=0.23), death rate (D=0.02) and generation time (G=20.14 days). The high rm/B (0.91) and B/D (11.50) ratios indicated the high colonizing ability of Ae. albopictus in nature.
A field study on foraging activity and proteinacous food preference was performed on the tropical fire ant (Solenopsis geminata) (Fabricius) at the School of Biological Sciences and Desasiswa Bakti Permai, Universiti Sains Malaysia (USM), Penang. Foraging activity studies of 4 colonies of S. geminata were conducted in the field for 24 hours. Foraging activity significantly increased 4 hours before sunset and maximum foraging occurred at midnight until early morning. Three types of proteinacous food; anchovy, meat and egg yolk were tested among the five colonies of S. geminata in the field. The egg yolk was the most preferred food (100%) followed by meat (31%) and anchovy (15%).