Hytrosaviridae as a threat to the Acknowledgments success application of SIT for Glossina pallidipes Andrew Parker Marc Vreysen Alan Robinson Max Bergoin Adly Abd-Alla Abd Elnaser Elashry François Cousserans Just Vlak Adun Henry Monique van Ores Mehrdad Ahmadi Insect Pest Control Laboratory, Ikbal Agah Ince Abdul Hasim Sjef Boeren Joint FAO/IAEA Division of Nuclear Techniques in Food Rudi Boigner and Agriculture, Vienna, Austria Henry Kariithi Edgardo Lapiz Carmen Marin Drion Boucias Verena Lietze Thanks to many Tamer Salem partners in African A. Garcia-Maruniak countries for providing Johannes Jehle James Maruniak wild tsetse samples Yongjie Wang Atoms for Food and Agriculture: Meeting the Challenge

Tsetse and Poverty Disease Control • 36 African In the absence of : countries 1)Sensitive diagnostic • 60 million people tools VECTOR CONTROL Tsetse- 2) Vaccine infested • 50 million cattle area in Africa 50 million cattle - Insecticides Humans: sleeping sickness - Sterile insect technique (SIT) • 300 – 500 thousands people infected • $ 3.5 million lost $ 3.5 million lost Mass production Livestock: Nagana Sterilization • 3 million cattle lost / year Male release • Cost: > $ 35 million/ year • potential loses : $ 4.5 billion G. pallidipes Rearing G. pallidipes in FAO/IAEA SGH Syndrome in tsetse laboratory SGH Syndrome in tsetse  Since 1980: G. pallidipes colony from Uganda  SGH (Whitnall, 1934) maintained  Glands enlarged >4 times  1996 : G. pallidipes colony established from Ethiopia   2000: Ethiopian colony reached 15,000 female -like particles in SGH (Jenni, 1973) SGHV (Jaenson,1978)  2001-2: Ethiopian colony productivity declined and colony became extinct Length: 700-1000 nm  >85% of individuals with SGH syndrome Diameter : 50 nm Assumption: colony decline was due to the virus

ImpactImpact ofof SGHVSGHV onon TsetseTsetse ReproductionReproduction Virus problem in Ethiopia The G. pallidipes colonies  Males with SGH completely sterile  In Seibersdorf: SGH low   In Ethiopia: SGH high Progeny of females with SGH fully sterile 50 Seibersdorf Ethiopia Linear (Ethiopia) Linear (Seibersdorf ) 45 43.5 39.6  40 For SIT - major problem - no large scale release 35

30 27  25 22.4 Supported assumption: the virus caused the 20

15 collapse of the G. pallidipes colony originating 10.6 SGH Prevalenve (%) 10 10 10.33 from Ethiopia in the FAO/IAEA laboratory in 10 8 2002 5 3 0 2003 2006 2007 2008 2009 2010 Overall Objective Specific objectives

 Detection and assessment of virus infection PCR and qPCR, wide asymptomatic infection

Obtain virus-free tsetse colonies  Characterize and sequence virus genome Or at least Sequence the genome of Uganda and Ethiopia isolates  Epidemiology and virus transmission Manage virus contamination to Vertical transmission in field, Horizontal transmission in colony maintain colony productivity  Genetic analysis of SGHV in wild tsetse and survival

  Develop virus management strategies

Virus management strategies Membrane feeding system  4-10 cages fed successively on the same membrane  1. Membrane feeding system modification  Favours horizontal virus transmission 10

9 7.04 2. Virus specific antibodies 8 7

6

5 4.49 3. Commercial antiviral drugs 4 3.32

3 2.33

2

1 4. RNAi number) copy (virus Log10 0 Clean Clean Clean Normal feeding feeding feeding feeding F0 F1 F2 Clean feeding tsetse colony established Membrane feeding system Clean feeding system  Clean feeding colony maintained for six months Advantages  Virus infection tested by PCR, qPCR and fly Simple and efficient way to reduce virus dissections infection load in small tsetse colonies

9 % of virus infection % of symptomatic flies 7.58 30 8

7 25 Disadvantages

6 20 4.61  5 Labour intensive 15 4  10 3 More equipment needed % of virus% infection

Log10 virus copy number 2 5 1 0 Other virus management strategies should 0 Standard colony Clean feeding colony Normal feeding Clean feeding Tsetse colonies Tsetse colony be developed Virus load decreasing in the clean feeding colony

Virus management strategies Antiviral drugs Nimaviridae

S A SSV V

E L

L SW

h

D D

V P

V V

I E I

8 E

I I

1 s 1

V

V 6 V m

6

1 6 A P A

A bE

t P t C

I I

V bC V V 1 1. Membrane feeding system modification Ap MV 0 10 Vac M 98 fR V 99 100 McV 86 40 00 61 1 32 RHV 78 13 100 100 28 88 0 98 0 ASF

1 Asfarviridae 9 2. Virus specific antibodies 9

9 9 V1 9 9 BH 1 0 0 V C C P uniN Herpesviridae 1 PV 0 B 0 6 N ele H NP H 0 V 0 1 C p V G V A V H  H L c  G d M G 3. Commercial antiviral drugs S M S N d p P N G V M P V Baculoviridae * Hytrosaviridae Hytrosaviridae 4. RNAi

V V

N V

1

b 1

N N

- -

r r

G

V V O

0.5 O

N N

z z

H H

Nudiviruses Antiviral drugs Antiviral drugs Selection of antiviral products  Toxicity to tsetse flies Conclusions  Availability  Valacyclovir and acyclovir at 300 µg/ml: slight  Efficiency  reduction in virus copy number Price   Effect on productivity and survival Valacyclovir could be applied in large scale Two products were selected tsetse rearing :  Valacyclovir  Acyclovir • No negative impact • Economically affordable esterases • Combination with CFS  More antiviral drugs should be screened Valacyclovir is a prodrug, an esterified version of acyclovir that has greater oral bioavailability (about 55%) than acyclovir (10 -20%).

Males with SGH are sterile Flies with SGH Females with contaminate blood SGH are sterile in F 1

Clean feeding: low virus load Flies infected by contaminated blood

Virus injection: no SGH In F 0 Oral infection: no SGH In F 0

Progeny of injected Virus injection: flies: high virus load increase the virus load