Larval aggregation on a burned human remain

Abstract. 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.

Life table of Synthesiomyia nudiseta (Van der Wulp) (Diptera: Muscidae) under uncontrolled laboratory environments – a preliminary study

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 (Ro= 108.6), mean generation time (To= 12.2), intrinsic rate of increase (rm= 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.

Breeding patterns of the JE vector Culex gelidus and its insect predators in rice cultivation areas of northern peninsular Malaysia

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.

Species composition of adult Anopheles populations and their breeding habitats in Hulu Perak district, Peninsular Malaysia.

Using the cow-baited trap (CBT) method, 1,845 Anopheles mosquitos, comprising 14 species, were caught in malaria-endemic area of Hulu Perak district, Peninsular Malaysia. The two dominant species were An. barbirostris (18.59%) and An. aconitus (18.86%). Anopheles maculatus, the main malaria vector, constituted 9.11% of the total number of mosquitos sampled. Three hundred and seventy-seven Anopheles larvae, comprising 8 species, were sampled using the North Carolina Biological Station dipper. Anopheles barbirostris larvae amounted to 64.69% of the total number of larvae; An. aconitus accounted for 10.65% of larvae. Seven habitats were identified as breeding places of Anopheles. Most species were found to breed in paddies, fishponds, and rivers. Other less popular habitats were temporary pools, mountain streams, and spring wells.

A study on some aspects of the epidemiology of malaria in an endemic district in northern Peninsular Malaysia near Thailand border.

A study on the distribution of malaria in Hulu Perak district, Peninsular Malaysia was carried out between January and December 1993. The study encompassed the distribution of malaria cases according to sex, age and profession. A total of 332 cases were recorded, with 182 cases occurring in males. The highest infection was observed in the above 15 years old age group. Forest workers (loggers, rattan collectors and forest product gatherers) were the group most exposed to the disease (32.8%), followed by both plantantion workers (32.2%) and aboriginal communities (32.2%). Army and police personnels (2.1%) were also infected. Plasmodium falciparum was the most common species of malaria in the area.

A report of Anopheles (Diptera: Culicidae) attracted to cow bait in a malaria endemic village in Peninsular Malaysia near the Thailand border.

Twelve species of Anopheles were collected by using cow-baited net trap in a malarial endemic village in northern Peninsular Malaysia. Anopheles maculatus which is the main malaria vector with its densities were related to drought. An. aconitus, An. kochi and An. philippinensis were less susceptible to P. falciparum and P. vivax infection, and are not considered important in falciparum or vivax malaria transmission. Biting activities of An. kochi and An. vagus were primarily active after dusk and steadily declined after midnight. An. maculatus and An. aconitus showed biting activities throughout the night but An. maculatus showed two peaks of biting activity in the first half of the night.