BackgroundRift Valley fever (RVF) is an acute febrile arthropod-borne viral disease of man and animals caused by a member of the Phlebovirus genus, one of the five genera in the family Bunyaviridae. RVF virus (RVFV) is transmitted between animals and human by mosquitoes, particularly those belonging to the Culex, Anopheles and Aedes genera.MethodsExperiments were designed during RVF outbreak, 2007 in Sudan to provide an answer about many raised questions about the estimated role of vector in RVFV epidemiology. During this study, adult and immature mosquito species were collected from Khartoum and White Nile states, identified and species abundance was calculated. All samples were frozen individually for further virus detection. Total RNA was extracted from individual insects and RVF virus was detected from Culex, Anopheles and Aedes species using RT-PCR. In addition, data were collected about human cases up to November 24th, 2007 to asses the situation of the disease in affected states. Furthermore, a historical background of the RVF outbreaks was discussed in relation to global climatic anomalies and incriminated vector species.ResultsA total of 978 mosquitoes, belonging to 3 genera and 7 species, were collected during Sudan outbreak, 2007. Anopheles gambiae arabiensis was the most frequent species (80.7%) in White Nile state. Meanwhile, Cx. pipiens complex was the most abundant species (91.2%) in Khartoum state. RT-PCR was used and successfully amplified 551 bp within the M segment of the tripartite negative-sense single stranded RNA genome of RVFV. The virus was detected in female, male and larval stages of Culex and Anopheles species. The most affected human age interval was 15-29 years old followed by ≥ 45 years old, 30-44 years old, and then 5-14 years old. Regarding to the profession, housewives followed by farmers, students, shepherd, workers and the free were more vulnerable to the infection. Furthermore, connection between human and entomological studies results in important human case-vulnerability relatedness findings.ConclusionModel performance, integrated with epidemiologic and environmental surveillance systems should be assessed systematically for RVF and other mosquito-borne diseases using historical epidemiologic and satellite monitoring data. Case management related interventions; health education and vector control efforts are extremely effective in preparedness for viral hemorrhagic fever and other seasonal outbreaks.

BackgroundDefensins are a well known family of cationic antibacterial peptides (AMPs) isolated from fungi, plants, insects, mussels, birds, and various mammals. They are predominantly active against gram (+) bacteria, and a few of them are also active against gram (-) bacteria and fungi. All insect defensins belonging to the invertebrate class have a consensus motif, C-X5-16-C-X3-C-X9-10-C-X4-7-CX1-C. Only seven AMPs have already been found in different lepidopteran species. No report was published on the isolation of defensin from the Egyptian cotton leafworm, Spodoptera littoralis.ResultsAn anionic defensin, termed SpliDef, was isolated from the haemolymph of the cotton leafworm, S. littoralis, after bacterial challenge using differential display technique. Based on sequence analyses of the data, specific primers for full length and mature peptide of defensin were designed and successfully amplified 471 and 150 bp amplicons. The integration of the results revealed that the 471 bp-PCR product has one open reading frame (orf) of 303 bp long, including both start codon (AUG) and stop codon (UGA). The deduced peptide consists of a 23-residues signal peptide, a 27-residues propeptide and a 50-residues mature peptide with the conserved six-cysteine motif of insect defensins. Both haemolymph and expressed protein exhibited antibacterial activities comparable to positive control. The RT-qPCR indicated that it was more than 41-folds up-regulated at 48 h p.i.ConclusionOur results highlight an important immune role of the defensin gene in Spodoptera littoralis by cooperating with other AMPs to control bacterial infection.

Eleven domestic guinea pig corpses were employed as models for studying decomposition and insect succession in Benha city, Egypt, from April 2009 to March 2010. Ambient temperature, faunistic succession over time, and the rate of decay in different seasons were all compared. Results indicated that ambient temperature is the chief factor determining the seasonal variations in decay rate. The diversity of insect community increased as the state of decomposition advances. Members of Dermistidae and Forrmicidae were the first coleopteran and hymenopteran colonizers in all seasons. Sarcophaga, Wholfortia and Chrysomya was observed in spring and summer. Meanwhile, species of Wholfortia were absent in winter and Crysomya species were absent in fall. Patterns of insect succession occurred in a predictable sequence that varied across different seasons. The rate of corpse's decomposition was faster in summer and autumn as compared to spring and winter

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BackgroundVarious proteins that display carbohydrate-binding activity in a Ca2+-dependent manner are classified into the C-type lectin family. They have one or two C-type carbohydrate-recognition domains (CRDs) composed of 110–130 amino acid residues in common. C-type lectins mediate cell adhesion, non-self recognition, and immuno-protection processes in immune responses and thus play significant roles in clearance of invaders, either as cell surface receptors for microbial carbohydrates or as soluble proteins existing in tissue fluids. The lectin of Spodoptera littoralis is still uncharacterized.MethodologyA single orf encoding a deduced polypeptide consisting of an 18-residue signal peptide and a 291-residue mature peptide, termed SpliLec, was isolated from the haemolymph of the cotton leafworm, S. littoralis, after bacterial challenge using RACE-PCR. Sequence analyses of the data revealed that SpliLec consists of two CRDs. Short-form CRD1 and long-form CRD2 are stabilized by two and three highly conserved disulfide bonds, respectively. SpliLec shares homology with some dipteran lectins suggesting possible common ancestor. The purified SpliLec exhibited a 140-kDa molecular mass with a subunit molecular mass of 35 kDa. The hemagglutination assays of the SpliLec confirmed a thermally stable, multisugar-binding C-type lectin that binds different erythrocytes. The purified SpliLec agglutinated microorganisms and exhibited comparable antimicrobial activity against gram (+) and gram (−) bacteria too.ConclusionsOur results suggested an important role of the SpliLec gene in cell adhesion and non-self recognition. It may cooperate with other AMPs in clearance of invaders of Spodoptera littoralis.

The bean skinks were collected manually from Abu.Rawash, Giza, Egypt, separated according to size and investigated for H. gracilis infection. Intensity of parasitaemia was determined as slight (≤ 2% per 1000 counted erythrocytes), moderate (3-10% per 1000 counted erythrocytes) and high (11-20% per 1000 counted erythrocytes). Cx. (Cx.) pipiens L were reared under controlled laboratory conditions (20 + 1 °C, 60-70% RH and 10L: 14D photoperiod). Four groups of 3-4-day-old females, 50 individuals each, were starved 12 h prior to feeding. The first group was used to feed on parasite-free bean skink while the other groups were offered blood meals from slightly, moderately and highly infected lizards. The fully engorged females from each group were transferred separately to oviposition tubes and observed daily for longevity and reproductive capacity. Data were statistically analyzed by ANOVA using SPSS software, Ver., 15.0. The present study declared that the majority of naturally infected bean skinks were slightly infected. Generally the parasitic infections were costive to their host vector and this cost was manifested as a reduction in reproductive and transmission capacities. Preoviposition period was reduced by 15% and increased by 55% in case of mosquitoes fed on highly and moderately infected skinks, respectively, as compared to control. Fecundity was reduced by 48, 37 and 18% and fertility was reduced by 8, 3 and 6% in case of mosquitoes fed on highly, moderately, slightly infected skinks, respectively, as compared to control. No significant difference in the egg incubation period was observed between control and infected groups. Adult longevity was reduced by 40% in case of mosquitoes fed on highly infected skinks and increased approximately 2 folds in case of mosquitoes fed moderately and highly, infected skinks as compared to control. The present study suggested a decreased competence of Cx. (Cx.) pipiens in the hepatzoonosis disease circulation in nature when the infection intensity was high or moderate. On the other hand, the vector is a very strong candidate in the disease circulation in nature in case of slight intensity of infection.

Objective: Fungi are the main source of aflatoxin contamination in nature. The present study aimed to assess the role of the cosmopolitan mosquito species, Culex pipiens, in the circulation and dissemination of pathogenic fungi in nature, and to evaluate its capability to harbor these fungi. Materials and Methods: Fungi were isolated and identified from both, the external surface and the internal organs of the developmental stages and from the breeding environment of Cx. pipiens. Results: A total of 35 fungal isolates were isolated from both, the internal organs and the external surface of the developmental stages and from the breeding environment of Cx. pipiens. These isolates were identified as eleven Penicillium notatum isolates, eleven Aspergillus flavus isolates, six Rhizopus stolonifer isolates, four Candida albicans isolates, two Fusarium solani isolates, and one Aspergillus niger isolate. Antagonistic activity showed that the P. notatum growth inhibited the growth of the bacteria, Staphylococcus aureus. Conclusions: This study revealed that the different developmental stages of Cx. pipiens mosquito were capable of harboring many fungal species. Subsequently, this mosquito will be incriminated in the mechanical dissemination, circulation, and transmission of these fungi in nature, during its life cycle.