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Managing hytrosavirus infections in Glossina pallidipes colonies: feeding regime affects the prevalence of salivary gland hypertrophy syndrome.

Abd-Alla AM, Kariithi HM, Mohamed AH, Lapiz E, Parker AG, Vreysen MJ - PLoS ONE (2013)

Bottom Line: 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.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 10(9) virus copies in regular colonies to an average of 10(2.5) and eliminates the SGH syndrome from clean feeding colonies by28 months post implementation of this approach.

View Article: PubMed Central - PubMed

Affiliation: Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, Vienna, Austria. a.m.m.abd-alla@iaea.org

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 10(9) virus copies in regular colonies to an average of 10(2.5) 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 10(8) virus copy numbers to an average of 10(3) 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.

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Related in: MedlinePlus

Handling, feeding and management of tsetse colony.(A) Regular in vitro membrane feeding system, (B) intermediate phase, and (C) final phase of the clean feeding system.
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pone-0061875-g002: Handling, feeding and management of tsetse colony.(A) Regular in vitro membrane feeding system, (B) intermediate phase, and (C) final phase of the clean feeding system.

Mentions: The main Seibersdorf Tororo G. pallidipes colony (totalling ∼12,000 flies) was maintained to provide pupae for establishing the clean feeding colonies using existing resources (i.e. no increase in number of staff, feeding trays and silicone membranes) (Figure 2A). With the available 12 sets of trays and silicone membranes, each able to feed 4 fly cages, the size of the CFC-1 and CFC-2 colonies was limited to 48 cages each, each colony containing on average 2,500 male and female flies (the standard cage initially contains 60 females and 15 males). Initiation of the clean feeding colonies started with feeding teneral flies (4 cages/week) emerging from the main colony. Twelve weeks after starting the clean feeding, the CFC-1 colony reached 48 cages and a higher number of teneral flies emerged from this colony than the number required to maintain the colony size stable (Figure 2B). Therefore, excess teneral flies from CFC-1 were fed on the same membrane to establish CFC-2. Similarly, the CFC-2 colony reached 48 cages after 12 weeks by adding 4 cages of teneral flies each week. As a result of implementing the clean feeding protocol, the main Seibersdorf Tororo colony (∼10,000) was progressively replaced by the three colonies, i.e. the CFC-1 (∼2,500 flies), CFC-2 (∼2,500) and NFC (∼ 5,000 flies) (Figure 2C).


Managing hytrosavirus infections in Glossina pallidipes colonies: feeding regime affects the prevalence of salivary gland hypertrophy syndrome.

Abd-Alla AM, Kariithi HM, Mohamed AH, Lapiz E, Parker AG, Vreysen MJ - PLoS ONE (2013)

Handling, feeding and management of tsetse colony.(A) Regular in vitro membrane feeding system, (B) intermediate phase, and (C) final phase of the clean feeding system.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3646844&req=5

pone-0061875-g002: Handling, feeding and management of tsetse colony.(A) Regular in vitro membrane feeding system, (B) intermediate phase, and (C) final phase of the clean feeding system.
Mentions: The main Seibersdorf Tororo G. pallidipes colony (totalling ∼12,000 flies) was maintained to provide pupae for establishing the clean feeding colonies using existing resources (i.e. no increase in number of staff, feeding trays and silicone membranes) (Figure 2A). With the available 12 sets of trays and silicone membranes, each able to feed 4 fly cages, the size of the CFC-1 and CFC-2 colonies was limited to 48 cages each, each colony containing on average 2,500 male and female flies (the standard cage initially contains 60 females and 15 males). Initiation of the clean feeding colonies started with feeding teneral flies (4 cages/week) emerging from the main colony. Twelve weeks after starting the clean feeding, the CFC-1 colony reached 48 cages and a higher number of teneral flies emerged from this colony than the number required to maintain the colony size stable (Figure 2B). Therefore, excess teneral flies from CFC-1 were fed on the same membrane to establish CFC-2. Similarly, the CFC-2 colony reached 48 cages after 12 weeks by adding 4 cages of teneral flies each week. As a result of implementing the clean feeding protocol, the main Seibersdorf Tororo colony (∼10,000) was progressively replaced by the three colonies, i.e. the CFC-1 (∼2,500 flies), CFC-2 (∼2,500) and NFC (∼ 5,000 flies) (Figure 2C).

Bottom Line: 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.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 10(9) virus copies in regular colonies to an average of 10(2.5) and eliminates the SGH syndrome from clean feeding colonies by28 months post implementation of this approach.

View Article: PubMed Central - PubMed

Affiliation: Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, Vienna, Austria. a.m.m.abd-alla@iaea.org

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 10(9) virus copies in regular colonies to an average of 10(2.5) 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 10(8) virus copy numbers to an average of 10(3) 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.

Show MeSH
Related in: MedlinePlus