Viable Larva Research Articles

Ultrasound features of cutaneous myiasis: a rare case in a child.

Cutaneous myiasis is an infestation of the skin with larvae of some dipteran species. Among humans, Dermatobia hominis is the most frequently encountered dipteran responsible for cutaneous myiasis. This insect is endemic to tropical and subtropical regions, consequently, individuals travelling from non-endemic areas are most susceptible to infection due to a lack of prior exposure. Three clinical variants of myiasis are distinguished: furuncular, migratory, and wound myiasis. Furuncular myiasis represents the most common form among travelers, yet it is a rare cause of pediatric skin manifestations in developed countries. Limited awareness of this condition in non-endemic regions contributes to diagnostic challenges. In this scenario, ultrasound is useful in the diagnostic workup, enabling the identification of the viable larva.

The production of bioinsecticide using Bacillus thuringiensis

This study aims at determining the ability of Bacillus thuringiensis to induce a biocidal effect on mosquito larvae. The B. thuringiensis used in this work was isolated from soil samples obtained from the root of plantain trees in a garden at Umuoma community in Uli Town. Soil samples were subjected to high temperature of about 50oC in order to exclude other microbes that may contaminate the culture, B. thuringiensis was able to survive the heat condition because they are spore formers. To further enhance purity of the culture, the organism was cultured in Luria Bertani medium which is selective for Bacillus spp. Before the toxicity tests were carried out, various morphological tests such as endospore stain, Gram stain, macroscopic examination and biochemical tests such as starch hydrolysis, oxidase test, motility test, citrate test, methyl red test, indole test, sugar fermentation test and catalase test were carried out to identify the organism. The results showed the isolates to be Bacillus thuringiensis. To ensure the ability of the isolate to produce spores needed for toxicity testing, the isolate was subcultured in nutrient agar and incubated at 37oC for 7 days after which there was formation of spores in the growth medium. The isolate was then inoculated in sterile water containing mosquito larvae in other to test for its toxicity against the mosquito larvae. At intervals, observations were made to determine the rate at which the Isolates induce the lethal effects on the larvae by using the sterile loop to check for viable larva remaining at each set up. The viability is deduced from the ability of the viable larva to retain their motility when agitated with the sterile wire loop. The result for toxicity testing showed that set-up Pr1 had the highest number of dead larvae at 1 – 4 hours respectively, while Gr1 had the lowest number of dead larvae at 1. Statistical representation of the results showed that there was significant difference of p > 0.05 between time and the parasporal crystals of Bacillus thuringiensis against mosquito larva. Two- factor ANOVA without replication also showed that there was a significant difference between the set-­ups Pr1, Pr2, Gr1 and Db2, and the positive control used gave significant difference of p < 0.05. This study successfully demonstrated the toxicity of the parasporal crystals of Bacillus thuringiensis against mosquito larvae.

Application of interspecific Somatic Cell Nuclear Transfer (iSCNT) in sturgeons and an unexpectedly produced gynogenetic sterlet with homozygous quadruple haploid

Somatic cell nuclear transfer (SCNT) is a very promising cloning technique for reconstruction of endangered animals. The aim of the present research is to implement the interspecific SCNT (iSCNT) technique to sturgeon; one fish family bearing some of the most critically endangered species. We transplanted single cells enzymatically isolated from a dissociated fin-fragment of the Russian sturgeon (Acipenser gueldenstaedtii) into non-enucleated eggs of the sterlet (Acipenser ruthenus), two species bearing different ploidy (4n and 2n, respectively). Up to 12% of the transplanted eggs underwent early development, and one feeding larva (0.5%) was successfully produced. Interestingly, although this transplant displayed tetraploidism (4n) as the donor species, the microsatellite and species-specific analysis showed recipient-exclusive homozygosis without any donor markers. Namely, with regards to this viable larva, host genome duplication occurred twice to form tetraploidism during its early development, probably due to iSCNT manipulation. The importance of this first attempt is to apply iSCNT in sturgeon species, establishing the crucial first steps by adjusting the cloning-methodology in sturgeon’s biology. Future improvements in sturgeon’s cloning are necessary for providing with great hope in sturgeon’s reproduction.

Combined Effects of Temperature and Photoperiod on the Conditioning of the Flat Oyster (Ostrea edulis[Linnaeus, 1758]) in Winter

The flat oyster Ostrea edulis (Linnaeus, 1758) is a commercially valuable species in Europe. The production of O. edulis natural spat has decreased in the past, and it is insufficient to meet demand. Thus, the importance of hatcheries in the production of oyster spat is increasing. The conditioning of O. edulis broodstock may be improved by manipulating several external factors such as temperature, food supply, and photoperiod; however, few studies have reported the effect of these parameters on O. edulis gametogenesis and conditioning. In this report, the combined effects of temperature and photoperiod on broodstock conditioning of O. edulis in winter were studied to provide a protocol that improves flat oyster conditioning. After a resting period in autumn, in winter, oysters' gonads are restructured, and the natural process of gonadal maturation is initiated. Oyster gonads showed follicles in intermediate maturation stages, with the presence of both male and female germinal cells in the same follicles but at different stages of maturation. The combined effect of temperature (TG14-18) and photoperiod on oyster conditioning in winter was evaluated by using direct indexes. Oysters conditioned with a gradient of temperature and a gradient of daylight (PG8-16), a P16 regime or under natural environmental conditions began to spawn 4 wk after the beginning of conditioning. Oysters treated with a P8 regime needed a week more to start spawning. Spawning was a continuous process that lasted for 7 wk. When the total amount of released viable larva was compared, the positive influence of photoperiod was much more evident. Total larval production was two or three times higher in the oysters treated with a gradient of daylight (PG8-16). In summary, using the conditions of temperature and photoperiod described in this study (TG14-18 and PG8-16), it was possible to improve flat oyster conditioning in winter, producing an important amount of viable larvae over a period of 2 mo.

A new focus of autochthonous transmission of Cordylobia anthropophaga in Saudi Arabia

BackgroundCordylobia anthropophaga, is responsible for nodular cutaneous myiasis in sub-Saharan Africa. The fly has long been limited to tropical Africa except for Asir Province, Saudi Arabia. Al Baha Province; north of Asir has an ecological pattern close to that dominant in subtropical Africa. The Southern parts of Saudi Arabia, including Al Baha, are considered part of the Afro-tropical zoogeographical belt where C. anthropophaga is dominant. A case, with cutaneous nodular lesions, was presented to us, where comprehensive investigations were done to establish the diagnosis and to relate it to the known epidemiological background. Materials and methodsA thorough history taking, comprehensive clinical examination and an intensive parasitological examination on a viable larva recovered from the cutaneous lesions, were performed. Taxonomic identification of the larva was done based on various criteria including shape, size, cuticle spine pattern and the posterior spiracles of the recovered larva. ResultsWe report a case of cutaneous myiasis, caused by Cordylobia anthropophaga, indigenously acquired in Al-Baha. The recovered larva was identified as the third instar of C. anthropophaga. With no history of travel to Africa or to Asir, along with a comprehensive epidemiological assessment, an autochthonous pattern of transmission was confirmed. ConclusionWe present a new focus of autochthonous transmission of C. anthropophaga in Saudi Arabia suggesting a need for an epidemiological reassessment. We also propose considering Cordylobia myiasis as a differential diagnosis in furuncular skin lesions, even in individuals with no history of traveling to Africa.

How small you can go: Factors limiting body miniaturization in winged insects with a review of the pantropical genus Discheramocephalus and description of six new species of the smallest beetles (Pterygota: Coleoptera: Ptiliidae)

The recently described and originally monotypic genus Discheramocephalus Johnson, 2007 from the Solomon Islands is revised. Six new species are described, illustrated and keyed: Discheramocephalus brucei sp. n. (Cameroon), D. elisabethae sp. n. (Cameroon), D. mikaeli sp. n. (Tanzania), D. stewarti sp. n. (Bolivia), D. jarmilae sp. n. (Bolivia), D. minutissimus sp. n. (Indonesia). Adults of D. minutissimus have a body length of about 400-426 µm, which is at the lower limit among non-egg- parasitoid insects. Evidence is provided that an egg size large enough to produce a viable larva is the main factor limiting miniaturi- sation of female insects. Females and males of egg-parasitoids are able to overcome the 400 µm threshold and reach limits of 180 µm and 130 µm, respectively. Brain size is likely the second most important factor limiting miniaturisation in insects.

A Note On Survival Of Infective Stage Larva Of Gnathostoma Spp. In BME Culture Medium

Dear editor, human gnathostomiasis in an important tropical parasitic infection ( 1). The major manifestation as nodular migratory eosinophilic panniculitis is suggested for this disease. More severe presentations, resulting from visceral larva migran, such as ocular and CNS gnathostomiasis are also reported. The diagnosis is confirmed by identification of the parasite from the pathological specimen. However, it is difficult to get the histological diagnosis, therefore, the immunological diagnosis for this infection is necessary. At present, Gnathostoma spinigerum third stage larvae (L3) antigen is necessary for Western blot analysis in the diagnosis of Gnathostomiasis ( 2 , 3). Acid pepsin solution is required for digestion of eel's liver (Fluta alba) to yield the larvae for antigen preparation. However, the specific antigen is excretion secretory (ES) antigen, which can be derived from viable larva. Since the larva start to degenerate within a short period, therefore, the larva derived from digestion must be used before its death. Here, we reported our result in using the BME culture medium for cultivation of the derived larva to prolong the period of usage of the harvested larva in antigen preparation.

Nutrition, hormones and life history in burying beetles

Nutrition, hormones and the allocation of physiological resources are intricately related. To investigate these inter-relationships in female burying beetles ( Nicrophorus spp.), we examined the effect of diet quality on juvenile hormone (JH) levels and reproduction, and the effect of JH supplementation on reproduction and resistance to starvation. Nicrophorus orbicollis adult females fed a less preferred mealworm larvae diet gained less body mass, had smaller ovaries and had lower titers of JH in their hemolymph than females fed a preferred blowfly diet. When presented a carcass for breeding, females on a less preferred diet oviposited 33% fewer eggs, and eggs were of 18% less mass. Females on the less preferred diet also took longer to begin oviposition as indicated indirectly by the time when their eggs hatched. To investigate the effects of JH, independent of nutrition, JH was topically applied to single and paired females of Nicrophorus tomentosus. When presented a carcass, JH-treated paired females oviposited more eggs (28%—year 1, 44%—year 2) than control females, and also showed a trend toward faster oviposition. JH supplementation had a greater effect on single females. JH treatment increased the proportion of single females attempting reproduction (at least one viable larva), increased the number of eggs (69%—year 1, 123%—year 2), and increased the proportion of females ovipositing early. In separate experiments, treatment with JH or a JH analog negatively affected resistance to starvation in three species. Treatment with JH reduced starvation survival by 10.3% days in N. tomentosus females. Treatment with the JH analog methoprene reduced starvation survival 17.8% in N. orbicollis females and by 18% in Ptomascopus morio females. These results suggest that JH has positive and negative effects on different components of life history.

Incubation of embryos and larvae of marine fish using microtiter plates

Egg quality can be defined using various parameters, but in the aquaculture industry it is defined as the potential of an egg to hatch into a viable larva (Kjorsvik et al., 1990; Brooks et al., 1997). The decision to stock a batch of eggs for production is firstly based on the fertilization % of the particular spawn, and then on the hatching % and survival to first feeding, i.e. when the mouth has opened (Bromage, 1995). When carrying out reproduction experiments, the ultimate success of the broodstock management or hormone treatment is determined by the production of good quality eggs. Evaluation of the fertilization % of different batches of eggs is easy, can be carried out within a few hours from spawning and does not require special facilities to keep the eggs. Evaluation of hatching % and survival to first feeding, however, requires maintaining the eggs for at least 5 d in the case of marine species such as the gilthead seabream (Sparus aurata) (Zohar et al., 1995) and the European seabass (Dicentrarchus labrax) (Carrillo et al., 1995). Maintaining a large number of egg batches produced from multi-factorial experiments in commercial-type incubators is unfeasible, due to space and cost constraints. Development of an incubation method which does not require extensive facilities will enable monitoring of egg quality from many different spawns or

Longitudinal studies of skin microfilaria and antibody conversion rates in children living in an endemic focus of onchocerciasis in Nigeria.

We monitored skin microfilarial conversion and antibody (serum) conversion rates to Onchocerca volvulus recombinant antigens (OC3.6 and OC9.3) over a 2-year period, in a cohort of 208 children aged 9-11 years and living in a mesoendemic focus of savannah-type onchocerciasis in Nigeria in order to detect prepatent onchocerciasis in children. Between time point A and time point B (9 months apart) the seroconversion rate was 19.4 per cent, and between time points B and C (15 months apart), a further 31.4 per cent of seronegative children had seroconverted. However, only a third of the seroconverted children became microfilaria-positive. From the time-lag between antibody conversion and skin snip conversion, we estimated that a 9-12 month interval was required for the detection of O. volvulus microfilariae following infection with viable third stage larva (L3s). The predictive value of antibody detection as a measure of skin microfilarial conversion was >90 per cent when the optical density (OD) at 490 nm was >0.80. We therefore propose a strategy for monitoring changes in transmission of onchocerciasis following vector control or chemotherapy through an evaluation of annual antibody seroconversion rates in a standardized sentinel population of children.

Cerebral cysticercosis: A case report

A case of cerebral cysticercosis is reported in a 49-year-old female who presented with headache, nausea, and vomiting. Lumbar CSF showed the findings of mild aseptic meningitis. CT scan revealed an enlargement of the left ambient cistern and a small cystic lesion in the left frontal cortex. MRI demonstrated multilobular cysts in the left ambient cistern with enhancement of their capsules, which compressed and distorted the midbrain. The cysts were surgically excised, and histological examination of the specimen disclosed characteristic features of cysticercus with viable larva. An excellent value of MRI in the diagnosis of intracisternal cysticercosis is emphasized.

Ovulation, insemination and mating in the tsetse fly Glossina pallidipes

ABSTRACT. Analyses of the ovulation, insemination and mating of female Glossina pallidipes Austen, were carried out in the field and laboratory. In unmated females, ovulation was delayed until at least the fifteenth day of adult life. The predictable pattern of growth and development of eggs was used to age nulliparous females to the nearest day in the field. Inseminated females first appeared at 5–6 days old and most females became inseminated at 8–10 days of age. There were no significant differences in the age at insemination in Zimbabwe or Kenya. Ovulation had occurred in the field by 10–11 days old. Mating therefore occurs at or just before ovulation. Females were able to mate at up to 12 days old and still produce a viable larva from their first egg. In laboratory flies originating from Uganda, factors which reduced and minimized the effects of disturbance, maximized insemination rate, so that under the best conditions the age at mating was identical to that found in the field. Nevertheless, the insemination rate of Fl generation Zimbabwe flies reared from wild‐caught females was negligible. The differences in the laboratory mating behaviour of the Zimbabwe flies and the flies from the long‐established colony of Uganda origin, are considered to be due to wild G. pallidipes being easily disturbed under laboratory conditions, whereas colony breeding rapidly selects for passivity. The concept of gross differences in G. pallidipes mating behaviour between geographic areas in thus rejected.

Invasive anisakiasis: A case report from Hawaii

A confirmed case of penetration into the stomach wall by an anisakine nematode, to our knowledge the first in the United States, is reported. A viable third-stage larva of Anisakis simplex was removed from a woman in Hawaii who had eaten fresh, raw salmon. A serodiagnostic test showed the serum of the patient to be positive for A. simplex-specific IgE at days 11 and 60 postinfection. Our results indicate that eating fresh, raw salmon exposes consumers to a significant health risk.

OVARY STRUCTURE AND REPRODUCTIVE BIOLOGIES OF LARVAL PARASITOIDS OF THE ALFALFA WEEVIL (COLEOPTERA: CURCULIONIDAE)

AbstractTwo manners in which parasitic Hymenoptera gather reproductive proteins are described. Hydropic species gather all protein necessary for reproduction as larvae. Only 5–10% of the material necessary to form a viable first instar larva is put into each egg; the remainder is gathered by the egg within the host. Egg storage is in the lateral oviducts, handling times are short and egg production is independent of host density. Three Bathyplectes spp. are examples of hydropic parasitoids. Anhydropic species gather some or all protein as adults, often by host feeding. All the material necessary for the formation of a viable first instar larva is stored within the egg. The eggs are held in the ovary until laid. Handling times are longer and continued egg production is dependent upon host density. Tetrastichus incertus (Ratzeburg) is an anhydropic parasitoid.Hydropic parasitoids appear best suited for biological control efforts in ephemeral situations (i.e. cotton or alfalfa). Anhydropic parasitoids appear best suited for biological control efforts in stable situations (i.e. citrus or walnuts).

Evolution of Egg Size Strategies in Fairy Shrimps

Differences exist among fairy shrimps in the size of the eggs they develop. Large eggs that hatch into big larvae probably evolved in the relatively predictable melt-pond environment as a result of selection against small size by invertebrate predators. High density-independent mortality occurring in the absence of predation on larval stages seems to have selected for the production of increased clutch size at the expense of egg volume in the unpredictable rain-pond habitat. Differences in resource availability between the two habitats along with r- and K-selection may have aided in the evolution of ecologically relevant egg sizes. Egg size is an important measure of a female fairy shrimp's invest- ment in each of her offspring. Assuming a lower limit is established by the minimum amount of material and energy required to produce a viable larva, optimality theory predicts that realized egg dimensions will be adjusted by natural selection to those which maximize indi- vidual fitness within a given environmental context. Recently, Wil- bur, Tinkle, and Collins (1974) discussed environmental certainty, trophic level, and resource availability as significant selective factors in the evolution of life history characteristics. In this paper, I discuss how these factors seem to account for egg size difference among fairy shrimps living in difference habitats.

Some effects of allatectomy in the female tsetse, Glossina austeni

The effects of juvenile hormone on the milk gland, ovaries, and fat body of adult female G. austeni were studied by allatectomy and hormone replacement therapy. In the absence of juvenile hormone, milk synthesis is slow, leading to the production, in a few cases, of small larvae over a prolonged inter-larval period. In most cases, no viable larva is produced and the fat body hypertrophies. Replacement of the corpus allatum with C 16JH leads to a rapid synthesis of milk, production of normal-sized larvae and a reversal of the effect on the fat body. It is therefore suggested that the milk gland activity is directly influenced by JH. Allatectomy in most cases also results in only one egg being matured. The others do not enter vitellogenesis. Similarly, this effect on the ovaries can be reversed by topical application of C 16JH.