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Virology, Epidemiology and Pathology of Glossina Hytrosavirus, and Its Control Prospects in Laboratory Colonies of the Tsetse Fly, Glossina pallidipes (Diptera; Glossinidae)  [PDF]
Henry M. Kariithi,Monique M. van Oers,Just M. Vlak,Marc J. B. Vreysen,Andrew G. Parker,Adly M. M. Abd-Alla
Insects , 2013, DOI: 10.3390/insects4030287
Abstract: The Glossina hytrosavirus (family Hytrosaviridae) is a double-stranded DNA virus with rod-shaped, enveloped virions. Its 190 kbp genome encodes 160 putative open reading frames. The virus replicates in the nucleus, and acquires a fragile envelope in the cell cytoplasm. Glossina hytrosavirus was first isolated from hypertrophied salivary glands of the tsetse fly, Glossina pallidipes Austen (Diptera; Glossinidae) collected in Kenya in 1986. A certain proportion of laboratory G. pallidipes flies infected by Glossina hytrosavirus develop hypertrophied salivary glands and midgut epithelial cells, gonadal anomalies and distorted sex-ratios associated with reduced insemination rates, fecundity and lifespan. These symptoms are rare in wild tsetse populations. In East Africa, G. pallidipes is one of the most important vectors of African trypanosomosis, a debilitating zoonotic disease that afflicts 37 sub-Saharan African countries. There is a large arsenal of control tactics available to manage tsetse flies and the disease they transmit. The sterile insect technique (SIT) is a robust control tactic that has shown to be effective in eradicating tsetse populations when integrated with other control tactics in an area-wide integrated approach. The SIT requires production of sterile male flies in large production facilities. To supply sufficient numbers of sterile males for the SIT component against G. pallidipes, strategies have to be developed that enable the management of the Glossina hytrosavirus in the colonies. This review provides a historic chronology of the emergence and biogeography of Glossina hytrosavirus, and includes researches on the infectomics (defined here as the functional and structural genomics and proteomics) and pathobiology of the virus. Standard operation procedures for viral management in tsetse mass-rearing facilities are proposed and a future outlook is sketched.
Managing Hytrosavirus Infections in Glossina pallidipes Colonies: Feeding Regime Affects the Prevalence of Salivary Gland Hypertrophy Syndrome  [PDF]
Adly M. M. Abd-Alla, Henry M. Kariithi, Abdul Hasim Mohamed, Edgardo Lapiz, Andrew G. Parker, Marc J. B. Vreysen
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0061875
Abstract: Many species of tsetse flies are infected by a virus that causes salivary gland hypertrophy (SGH) syndrome and the virus isolated from Glossina pallidipes (GpSGHV) has recently been sequenced. Flies with SGH have a reduced fecundity and fertility. Due to the deleterious impact of SGHV on G. pallidipes colonies, several approaches were investigated to develop a virus management strategy. Horizontal virus transmission is the major cause of the high prevalence of the GpSGHV in tsetse colonies. Implementation of a “clean feeding” regime (fresh blood offered to each set of flies so that there is only one feed per membrane), instead of the regular feeding regime (several successive feeds per membrane), was among the proposed approaches to reduce GpSGHV infections. However, due to the absence of disposable feeding equipment (feeding trays and silicone membranes), the implementation of a clean feeding approach remains economically difficult. We developed a new clean feeding approach applicable to large-scale tsetse production facilities using existing resources. The results indicate that implementing this approach is feasible and leads to a significant reduction in virus load from 109 virus copies in regular colonies to an average of 102.5 and eliminates the SGH syndrome from clean feeding colonies by28 months post implementation of this approach. The clean feeding approach also reduced the virus load from an average of 108 virus copy numbers to an average of 103 virus copies and SGH prevalence of 10% to 4% in flies fed after the clean fed colony. Taken together, these data indicate that the clean feeding approach is applicable in large-scale G. pallidipes production facilities and eliminates the deleterious effects of the virus and the SGH syndrome in these colonies.
Identification of landing Site Preference of Fully-fed Glossina pallidipes and Glossina morsitans (diptera: glossinidae)  [PDF]
Nyengerai, T.,Gori, E.,Mwandiringana, E.,Mushayi, W.
Journal of Environmental Issues and Agriculture in Developing Countries , 2012,
Abstract: An experiment to identify landing sites of fully fed Glossina pallidipes and Glossina morsitans was set up at the end of the winter season in Zimbabwe at Rukomichi Research Station. Five experiments subjected to three treatments differing in duration of catch, interval of catch and landing position were performed. A mean catch of 13 was recorded for 15-minute interval catches on logs wrapped in black cloth for the same species. Site and treatment had a significant effect on mean catch levels for Glossina morsitans (LSD=0.0979) and Glossina pallidipes (LSD=0, 1409). The mean catch (1644) for both fully fed Glossina morsitans and Glossina pallidipes was highest for 15-minute interval catches on unwrapped upright logs. This was twice higher than the overall mean catch recorded for continuous catch on unwrapped upright logs indicating the repellent effect of man on Glossina morsitans and Glossina pallidipes. Unwrapped upright logs could alternatively be used to catch Glossina pallidipes and Glossina morsitans after feeding for the purpose of biological and chemical assays to determine the effectiveness of chemicals on trials. This could also avoid the rubbing effect on the animal body and hence eliminating contamination on the hand-nets.
Genetic diversity and population structure of Glossina pallidipes in Uganda and western Kenya
Johnson O Ouma, Jon S Beadell, Chaz Hyseni, Loyce M Okedi, Elliot S Krafsur, Serap Aksoy, Adalgisa Caccone
Parasites & Vectors , 2011, DOI: 10.1186/1756-3305-4-122
Abstract: AMOVA indicated that differences among sampling sites explained a significant proportion of the genetic variation. Principal component analysis and Bayesian assignment of microsatellite genotypes identified three distinct clusters: western Uganda, southeastern Uganda/Lambwe Valley, and Nguruman in central-southern Kenya. Analyses of mtDNA confirmed the results of microsatellite analysis, except in western Uganda, where Kabunkanga and Murchison Falls populations exhibited haplotypes that differed despite homogeneous microsatellite signatures. To better understand possible causes of the contrast between mitochondrial and nuclear markers we tested for sex-biased dispersal. Mean pairwise relatedness was significantly higher in females than in males within populations, while mean genetic distance was lower and relatedness higher in males than females in between-population comparisons. Two populations sampled on the Kenya/Uganda border, exhibited the lowest levels of genetic diversity. Microsatellite alleles and mtDNA haplotypes in these two populations were a subset of those found in neighboring Lambwe Valley, suggesting that Lambwe was the source population for flies in southeastern Uganda. The relatively high genetic diversity of G. pallidipes in Lambwe Valley suggest large relict populations remained even after repeated control efforts.Our research demonstrated that G. pallidipes populations in Kenya and Uganda do not form a contiguous tsetse belt. While Lambwe Valley appears to be a source population for flies colonizing southeastern Uganda, this dispersal does not extend to western Uganda. The complicated phylogeography of G. pallidipes warrants further efforts to distinguish the role of historical and modern gene flow and possible sex-biased dispersal in structuring populations.Glossina pallidipes is a major vector of animal African trypanosomiasis. The vector has also been implicated in the transmission of Human African Trypanosomiasis (HAT). For example, the expa
Laboratory Colonisation and Genetic Bottlenecks in the Tsetse Fly Glossina pallidipes  [PDF]
Marc Ciosi ,Daniel K. Masiga equal contributor,Charles M. R. Turner equal contributor
PLOS Neglected Tropical Diseases , 2014, DOI: 10.1371/journal.pntd.0002697
Abstract: Background The IAEA colony is the only one available for mass rearing of Glossina pallidipes, a vector of human and animal African trypanosomiasis in eastern Africa. This colony is the source for Sterile Insect Technique (SIT) programs in East Africa. The source population of this colony is unclear and its genetic diversity has not previously been evaluated and compared to field populations. Methodology/Principal Findings We examined the genetic variation within and between the IAEA colony and its potential source populations in north Zimbabwe and the Kenya/Uganda border at 9 microsatellites loci to retrace the demographic history of the IAEA colony. We performed classical population genetics analyses and also combined historical and genetic data in a quantitative analysis using Approximate Bayesian Computation (ABC). There is no evidence of introgression from the north Zimbabwean population into the IAEA colony. Moreover, the ABC analyses revealed that the foundation and establishment of the colony was associated with a genetic bottleneck that has resulted in a loss of 35.7% of alleles and 54% of expected heterozygosity compared to its source population. Also, we show that tsetse control carried out in the 1990's is likely reduced the effective population size of the Kenya/Uganda border population. Conclusions/Significance All the analyses indicate that the area of origin of the IAEA colony is the Kenya/Uganda border and that a genetic bottleneck was associated with the foundation and establishment of the colony. Genetic diversity associated with traits that are important for SIT may potentially have been lost during this genetic bottleneck which could lead to a suboptimal competitiveness of the colony males in the field. The genetic diversity of the colony is lower than that of field populations and so, studies using colony flies should be interpreted with caution when drawing general conclusions about G. pallidipes biology.
Impact of Salivary Gland Hypertrophy Virus Infection on the Mating Success of Male Glossina pallidipes: Consequences for the Sterile Insect Technique  [PDF]
Gratian N. Mutika, Carmen Marin, Andrew G. Parker, Drion G. Boucias, Marc J. B. Vreysen, Adly M. M. Abd-Alla
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0042188
Abstract: Many species of tsetse flies are infected by a virus (GpSGHV) that causes salivary gland hypertrophy (SGH). Female Glossina pallidipes (Austen) with SGH symptoms (SGH+) have reduced fecundity and SGH+ male G. pallidipes are unable to inseminate female flies. Consequently, G. pallidipes laboratory colonies with a high prevalence of SGH have been difficult to maintain and have collapsed on several occasions. To assess the potential impact of the release of SGH+ sterile male G. pallidipes on the efficacy of an integrated control programme with a sterile insect technique (SIT) component, we examined the mating efficiency and behaviour of male G. pallidipes in field cages in relation to SGH prevalence. The results showed in a field cage setting a significantly reduced mating frequency of 19% for a male G. pallidipes population with a high prevalence of SGH (83%) compared to 38% for a male population with a low prevalence of SGH (7%). Premating period and mating duration did not vary significantly with SGH status. A high percentage (>80%) of females that had mated with SGH+ males had empty spermathecae. The remating frequency of female G. pallidipes was very low irrespective of the SGH status of the males in the first mating. These results indicate that a high prevalence of SGH+ in G. pallidipes not only affects colony stability and performance but, in view of their reduced mating propensity and competitiveness, releasing SGH+ sterile male G. pallidipes will reduce the efficiency of a sterile male release programme.
The Salivary Secretome of the Tsetse Fly Glossina pallidipes (Diptera: Glossinidae) Infected by Salivary Gland Hypertrophy Virus  [PDF]
Henry M. Kariithi,Ikbal A. Ince,Sjef Boeren,Adly M. M. Abd-Alla,Andrew G. Parker,Serap Aksoy,Just M. Vlak ,Monique M. van Oers
PLOS Neglected Tropical Diseases , 2011, DOI: 10.1371/journal.pntd.0001371
Abstract: Background The competence of the tsetse fly Glossina pallidipes (Diptera; Glossinidae) to acquire salivary gland hypertrophy virus (SGHV), to support virus replication and successfully transmit the virus depends on complex interactions between Glossina and SGHV macromolecules. Critical requisites to SGHV transmission are its replication and secretion of mature virions into the fly's salivary gland (SG) lumen. However, secretion of host proteins is of equal importance for successful transmission and requires cataloging of G. pallidipes secretome proteins from hypertrophied and non-hypertrophied SGs. Methodology/Principal Findings After electrophoretic profiling and in-gel trypsin digestion, saliva proteins were analyzed by nano-LC-MS/MS. MaxQuant/Andromeda search of the MS data against the non-redundant (nr) GenBank database and a G. morsitans morsitans SG EST database, yielded a total of 521 hits, 31 of which were SGHV-encoded. On a false discovery rate limit of 1% and detection threshold of least 2 unique peptides per protein, the analysis resulted in 292 Glossina and 25 SGHV MS-supported proteins. When annotated by the Blast2GO suite, at least one gene ontology (GO) term could be assigned to 89.9% (285/317) of the detected proteins. Five (~1.8%) Glossina and three (~12%) SGHV proteins remained without a predicted function after blast searches against the nr database. Sixty-five of the 292 detected Glossina proteins contained an N-terminal signal/secretion peptide sequence. Eight of the SGHV proteins were predicted to be non-structural (NS), and fourteen are known structural (VP) proteins. Conclusions/Significance SGHV alters the protein expression pattern in Glossina. The G. pallidipes SG secretome encompasses a spectrum of proteins that may be required during the SGHV infection cycle. These detected proteins have putative interactions with at least 21 of the 25 SGHV-encoded proteins. Our findings opens venues for developing novel SGHV mitigation strategies to block SGHV infections in tsetse production facilities such as using SGHV-specific antibodies and phage display-selected gut epithelia-binding peptides.
The Antiviral Drug Valacyclovir Successfully Suppresses Salivary Gland Hypertrophy Virus (SGHV) in Laboratory Colonies of Glossina pallidipes  [PDF]
Adly M.M. Abd-Alla, Henry Adun, Andrew G. Parker, Marc J.B. Vreysen, Max Bergoin
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0038417
Abstract: Many species of tsetse flies are infected with a virus that causes salivary gland hypertrophy (SGH) symptoms associated with a reduced fecundity and fertility. A high prevalence of SGH has been correlated with the collapse of two laboratory colonies of Glossina pallidipes and colony maintenance problems in a mass rearing facility in Ethiopia. Mass-production of G. pallidipes is crucial for programs of tsetse control including the sterile insect technique (SIT), and therefore requires a management strategy for this virus. Based on the homology of DNA polymerase between salivary gland hypertrophy virus and herpes viruses at the amino acid level, two antiviral drugs, valacyclovir and acyclovir, classically used against herpes viruses were selected and tested for their toxicity on tsetse flies and their impact on virus replication. While long term per os administration of acyclovir resulted in a significant reduction of productivity of the colonies, no negative effect was observed in colonies fed with valacyclovir-treated blood. Furthermore, treatment of a tsetse colony with valacyclovir for 83 weeks resulted in a significant reduction of viral loads and consequently suppression of SGH symptoms. The combination of initial selection of SGHV-negative flies by non-destructive PCR, a clean feeding system, and valacyclovir treatment resulted in a colony that was free of SGH syndromes in 33 weeks. This is the first report of the use of a drug to control a viral infection in an insect and of the demonstration that valacyclovir can be used to suppress SGH in colonies of G. pallidipes.
Detection and characterization of Wolbachia infections in laboratory and natural populations of different species of tsetse flies (genus Glossina)
Doudoumis Vangelis,Tsiamis George,Wamwiri Florence,Brelsfoard Corey
BMC Microbiology , 2012, DOI: 10.1186/1471-2180-12-s1-s3
Abstract: Background Wolbachia is a genus of endosymbiotic α-Proteobacteria infecting a wide range of arthropods and filarial nematodes. Wolbachia is able to induce reproductive abnormalities such as cytoplasmic incompatibility (CI), thelytokous parthenogenesis, feminization and male killing, thus affecting biology, ecology and evolution of its hosts. The bacterial group has prompted research regarding its potential for the control of agricultural and medical disease vectors, including Glossina spp., which transmits African trypanosomes, the causative agents of sleeping sickness in humans and nagana in animals. Results In the present study, we employed a Wolbachia specific 16S rRNA PCR assay to investigate the presence of Wolbachia in six different laboratory stocks as well as in natural populations of nine different Glossina species originating from 10 African countries. Wolbachia was prevalent in Glossina morsitans morsitans, G. morsitans centralis and G. austeni populations. It was also detected in G. brevipalpis, and, for the first time, in G. pallidipes and G. palpalis gambiensis. On the other hand, Wolbachia was not found in G. p. palpalis, G. fuscipes fuscipes and G. tachinoides. Wolbachia infections of different laboratory and natural populations of Glossina species were characterized using 16S rRNA, the wsp (Wolbachia Surface Protein) gene and MLST (Multi Locus Sequence Typing) gene markers. This analysis led to the detection of horizontal gene transfer events, in which Wobachia genes were inserted into the tsetse flies fly nuclear genome. Conclusions Wolbachia infections were detected in both laboratory and natural populations of several different Glossina species. The characterization of these Wolbachia strains promises to lead to a deeper insight in tsetse flies-Wolbachia interactions, which is essential for the development and use of Wolbachia-based biological control methods.
Transgenerational Transmission of Addiction Problems  [PDF]
Amal Bernoussi, Joanic Masson, Alison Thierry, Ma?lle Nicolas
Open Journal of Medical Psychology (OJMP) , 2015, DOI: 10.4236/ojmp.2015.43008
Abstract: This paper aims to evaluate the possible transgenerational transmission of a mechanism of addiction triggered by a specific type of attachment and the prevalence of psychological trauma in the descendants. 22 adults (alcoholics, drug addicts, and heroin addicts) aged 23 to 56 followed in an addictology treatment centre are participated. Measurements: We evaluated the prevalence of family ascendants on our population using two semi structured interviews and a genogram. Potential psychological trauma was measured with the Child Trauma Questionnaire (CTQ) and the quality of attachment with the Attachment Style Questionnaire (ASQ). Findings: 95% of patients have direct ascendants who suffer from addiction. 86% of patients suffered emotional negligence during childhood. Physical abuse is frequent (41%) as well as emotional abuse (50%), which proves a form of mistreatment and explains the presence of an insecure attachment. Conclusion: Addicts have often been neglected and have lived in emotional deprivation during childhood, which is the reason for an insecure attachment. The ascendants, who often suffer from addiction themselves, have, because of their pathology, contributed to a possible transgenerational transmission of the mechanism of addiction via the quality of the affective links with their children.
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