This document discusses polychaetes as potential vectors for shrimp pathogens. It finds that several shrimp pathogens, including WSSV, have been reported to infect polychaetes living in shrimp ponds. The biology and ecology of polychaetes, such as living in burrows, filtering feedings, and being a natural food source for shrimp, allows them to acquire and transmit pathogens. Studies found WSSV present in the polychaete Dendronereis spp. at similar levels to infected shrimp, and transmission was shown to occur from the polychaete to shrimp. An ongoing study is investigating polychaetes as potential carriers of Enterocytozozoon hepatopenaei, the cause of

1. Polychaetes as
potential risk for
shrimp pathogen
transmission
Desrina, S. Budi Prayitno,
Johan Verreth, Marc Verdegem,
Just Vlak.
rinadesrina@yahoo.com

2. Polychaetes :
Benthic macro-invertebrate
Live in soft bottom estuarine and coastal
area: (shrimp pond )
Beneficial to traditional shrimp farming: natural
food

3. Shrimp pathogens reported occurs in polychaetes
WSSV : (Vijayan et al. 2005, Desrina et al. 2012,
Desrina et al. 2013, Haryadi et al. 2015)
VP AHPND and Enterocytozoon Hepatopenaei (EHP ) :
(Thitamadee et al. 2016).

4. Why Polychaetes?
Biology and ecology of Polychaetes facilitate
polychaetes to be vector/ carrier/host of shrimp
pathogen

5. Polychaetes in shrimp ponds:
1. Live in burrow
2. Feeding strategies: Filter feeder,
Detritovore , carnivore, omnivore.
3. Natural food of shrimp in pond

6. Live in burrow and errant polychaete
Bioturbation
- Avoid treatment
- Live inside the pond until die; long exposure time

7. Mature female: green
Mature male: whitish

8. 2. Feeding : Detritovore , carnivore,
omnivore.
Recycling nutrient
Acquire shrimp
pathogen through feeding

9. Natural food of shrimp
Polychaetes are transported cross nations
as brooder maturation diet

10. Study on WSSV infection in Dendronereis spp:
Findings and some reflection to study HPM and
AHPND

11. 1. WSSV load in Dendronereis spp. is comparable
to that in P.monodon
Findings and lesson learnt

12. Specimen One step
PCR
Nested -
PCR
RT-PCR
(WSSV copy /
µg total DNA
Dendronereis spp. N P ND
Dendronereis spp. N P NT
Dendronereis spp. P NA 1.9 x 104
Dendronereis spp. P NA 1.2 x 102
Dendronereis spp. P NA 1.5 x 102
Dendronereis spp. N P ND
Dendronereis spp. N P NT
Dendronereis spp. N N NT
P. monodon P NA 3.0 x 104
P. monodon P NA 1.57 x 105
P. monodon N P NT
Findings and lesson learnt

13. 2. WSSV widely occured in the
Dendronereis spp. in shrimp pond in
Indonesia
Semarang vicinity, Central Java
Mahakam Delta, East Kalimantan
3. Polychaete Dendronereis spp. harbour
high concentration of WSSV without Clinical
signs
Findings and lesson learnt

14. 4. Dendronereis spp is a WSSV host
IHC
Desrina et al.. 2013. Journal of
Invertebrate Pathology, 2013, 114: 7–
10.
RT-PCR
Natural infection
Findings and lesson learnt

15. 5. WSSV was transmitted from Dendronereis spp.
to healthy shrimp upon feeding
6. Infection in shrimp post transmission
tends to be dose dependent
Findings and lesson learnt

16. 7. WSSV infection in Dendronereis spp. was
associated with WSSV infection in shrimp and
Dendronereis spp. density
Findings and lesson learnt
8. Small Dendronereis spp. tend to be negative
with nested PCR: get the infection in the
pond

17. Investigation on polychaetes as carrier of
Enterocytozoon hepatopenaei in the
hepatopancreatic microsporidiasis (HPM)
outbreak in the shrimp ponds
On going study

18. 1. Collect polychaetes and shrimp from HPM
affected ponds in north coast of Java island (
West Java, Central Java and East Java).
2. Detected EHP with PCR, RT-PCR, histology, and
wet mount.
3. Transmission experiment
Research Plan

19. Polychaetes found in EHP affected ponds
Perinereis sp
Marphysa spp
Nereis sp

20. EHP was detected in wild Perinereis with
PCR and Histology (Henny Budi Utari, CP Prima)

21. Acknowledgement

22. Acknowledgment
• Shrimp farmers in Semarang (Central Java) and
Mahakam Delta (East Kalimantan).
• My students: Toha, Rendy, Pierre Hakeesteg, Mujib,
Awet, Yoyok and the A Team
• Dean of Faculty of Fisheries and Marine Sciences,
Diponegoro University, Semarang, Indonesia
• Prof. dr. Monique van Oers, Dr. Stineke van Houte
and Dr. Vera Ros, Virology Laboratory, Wageningen,
University.
• Dr. Jan Rombout (Retired, Wageningen University)
• RESCOPAR Project Coordinators (Roel Bosma, Paul
van Zwieten and Prof Syafei Sidik) 22

23. Point to ponder
Preventing shrimp pathogen does not only preventing
economic lost due to outbreaks, but also preventing
pathogen spill over to potential host(s) in the shrimp pond

24. Thank you
24
Terima kasih
Thank you