Effect of Type of Tissue on the Development of Chrysomya rufifacies (Diptera: Calliphoridae) in Sri Lanka.

Chrysomya rufifacies (Macquart), the hairy maggot blow fly, is of great importance for the field of forensic entomology due to its habit as an early colonizer of decomposing vertebrate remains and myiasis producer. Development studies on this species have been conducted in scattered regions of the world, using types of tissue from several species of animals as a rearing medium. Despite the commonality of C. rufifacies in Sri Lanka, developmental studies have never been performed in this region. As well, the effects of diet on development have not been tested. In the current study, C. rufifacies immatures were reared on skeletal muscle, liver, and heart from domestic swine, with flies from colonies maintained at 25 and 28°C. The minimum time needed to complete each stage at 25°C on liver (224.14 h) was fastest followed by skeletal muscle (249.33 h) and heart (251.64 h) respectively, whereas at 28°C, fly development was quickest on heart muscle (178.27 h) followed by liver (178.50 h) and skeletal muscle (186.17 h) respectively. A significant difference in total development time was determined for temperature, while the rearing medium was not significant. Temperature also showed a significant effect on the length and the width of the larvae, while the type of tissue statistically impacted only the width.

Effect of Temperature and Tissue Type on the Development of the Forensic Fly Chrysomya megacephala (Diptera: Calliphoridae).

Chrysomya megacephala Fabricius is one of the most common myiasis-causing and carrion-feeding fly species in the tropics. This species has a worldwide distribution due to globalization and therefore is of critical importance to the public health sector and forensic investigations. Development studies carried worldwide show that Ch. megacephala reared at similar temperatures may require different amounts of time to complete their cycle of growth. The present study determined for the first time the life-history information of this species in Sri Lanka. Chrysomya megacephala colonies were reared on three different food sources (bovine muscle, swine muscle, and swine liver) considering the most common forensic entomology rearing mediums and the capability of Ch. megacephala to cause myiasis in cattle. Furthermore, colonies were reared at four temperature regimes representing several specific development conditions of this blowfly: 1) 20°C representing the estimation of the lower developmental threshold for this species in Sri Lanka; 2) 25 and 27°C representing typical room/environmental temperatures in Sri Lanka; and 3) 38°C as this is the typical living animal temperature, representing myiasis conditions. Results show that temperature significantly affected larval length and width over time; however, tissue type was not a significant factor. The fastest development was recorded at 38°C for immature feeding on bovine muscle (162.15 h), followed by those fed swine liver (184.15 h) and swine muscle (208.00 h). The calculated minimum temperature threshold for Ch. megacephala was 13°C. Data generated will be crucial for future forensic investigations involving living or deceased individuals colonized by this species.

Effect of Temperature and Tissue Type on the Development of Myiasis Causing Fly; Chrysomya bezziana (Diptera: Calliphoridae).

Chrysomya bezziana Villeneuve is the major human myiasis producer in tropical countries, including Sri Lanka. Although of great medical and veterinary importance, only a single study has been published on the development of C. bezziana. This limitation is due in part to the difficulty of maintaining this species in a colony outside of using a living host. In this study, a novel technique that overcomes this limitation is presented along with development data for C. bezziana fed on three different meat types: swine muscle, swine liver, and bovine muscle at two temperature regimes: 35 and 37°C. The optimum development of C. bezziana was recorded at 35°C in bovine muscle (262.20 h) followed by swine muscle (286.00 h) and swine liver (307.00 h). Data from the current study indicate tissue type significantly impacts change in length and width of larvae over time, whereas the two temperatures examined had no significant effect.

Temperature and Tissue Type Impact Development of Lucilia cuprina (Diptera: Calliphoridae) in Sri Lanka.

Lucilia cuprina (Wiedemann; Diptera: Calliphoridae) is a facultative ecto-parasitic fly, distributed throughout the temperate and subtropical regions of the world. This blow fly species is of medical, veterinary, and forensic importance due to it being used in maggot debridement therapy (MDT), a causative agent of myiasis, and a decomposer of vertebrate carrion. The current study examined the combined effects of temperature and tissue type on the development of L. cuprina. Specimens were reared on three tissue types; swine muscle, swine liver, and bovine muscle at 20°C, 25°C, 27°C, and 38°C. The optimum condition for L. cuprina development was for immatures reared on bovine muscle (287.4 h) followed by those reared on swine muscle (288.0 h) and swine liver (288.4 h) at 27°C. The minimum temperature threshold of L. cuprina was deduced to be 14°C. No significant differences in larval width and length over time were determined for the tissue type.

Bee and wasp stings in Deniyaya; a series of 322 cases.

OBJECTIVES: To describe wasp and bee species that sting humans, analyse risk factors and clinical features. METHODS: A prospective observational study was conducted on patients presenting to Base Hospital Deniyaya with suspected bee and wasp stings from 2011 to 2013. Data were gathered using a questionnaire and specimens of offending insects collected for identification. When the insect specimen was unavailable, identification was made by the victim selecting (without prompting) from several dead specimens presented by the first author. RESULTS: There were 322 patients (mean age: 42.5 years, SD: 15.1, 173 [53.7%] males). Insects were brought by 55 (17%) and 267 (83%) were identified using specimens. All occurred during day-time, 142 (44.1%) during August and September, and 200 victims (62%) were tea plantation workers. Majority (78.9%) reported a localized painful self-limiting swelling without systemic features and 15 (4.6%) developed anaphylactic shock. None died. Five specimens were available from those in anaphylactic shock (four Apis dorsata, one Ropalidia marginata). Vespa tropica stinging caused a characteristic skin lesion. Of the 55 specimens, 46 (83.6%) were Apis dorsata (Giant honey-bee, ''Bambara''), 8 (14.5%) Vespa tropica (Greater banded hornet, ''Debara'') and one Ropalidia marginata (Paper wasp, ''Kaladuruwa''). CONCLUSIONS: Only three hymenoptera species stings were reported. Risk factors included day-time outdoor activities, occupation (tea plantation workers) and period of year. The latter may be due to pollen season when the insects are found in abundance. Only 4.6% of the patients developed anaphylactic shock. Vespa tropica stings led to a unique skin lesion.

First record of Megaselia scalaris (LOEW) (DIPTERA: PHORIDAE) infesting a spinose ear tick, Otobius megnini, colony in Sri Lanka.

Megaselia scalaris (Loew) is a cosmopolitan polyphagous small fly with the ability of exploiting variety of ecological niches. Different life history stages act as detritivore, parasite, and parasitoid of wider spectrum of plant and animal matter under natural and laboratory conditions. Here, for the first time we present the opportunistic parasitism of M. scalaris on Otobius megnini, which act as a vector of Q fever and is capable of causing paralysis, toxic conditions, otoacariasis and otitis in humans and other animals. Tick samples from the ear canals of 14 thoroughbred horses were brought to the laboratory and several days later, larvae of M. scalaris were found feeding on immature stages of O. megnini. When the development was completed pupae were found attached to adult ticks and all nymphs were found dead. This context reveals the capability of M. scalaris surviving on O. megnini and the risk of their invading ear canals of horses.

First record of Megaselia scalaris (LOEW) (DIPTERA: PHORIDAE) infesting a spinose ear tick, Otobius megnini, colony in Sri Lanka

Megaselia scalaris (Loew) is a cosmopolitan polyphagous small fly with the ability of exploiting variety of ecological niches. Different life history stages act as detritivore, parasite, and parasitoid of wider spectrum of plant and animal matter under natural and laboratory conditions. Here, for the first time we present the opportunistic parasitism of M. scalaris on Otobius megnini, which act as a vector of Q fever and is capable of causing paralysis, toxic conditions, otoacariasis and otitis in humans and other animals. Tick samples from the ear canals of 14 thoroughbred horses were brought to the laboratory and several days later, larvae of M. scalaris were found feeding on immature stages of O. megnini. When the development was completed pupae were found attached to adult ticks and all nymphs were found dead. This context reveals the capability of M. scalaris surviving on O. megnini and the risk of their invading ear canals of horses.