Tom Henderson, (Canterbury Health Laboratories, Quality Facilitator) presented this at the New Zealand Institute of Medical Laboratory Science's South Island Seminar in April 2013. This presentation on Tapeworms won Tom the Best Presenter award at the seminar.

1. DIPHYLLOBOTHRIUM-
HOMEGROWN OR FOREIGN
TRAVELLOR
A LABTECH PRESENTATION
By Tom Henderson

2. DIPHYLLOBOTHRIUM SP.
 Consists of at least 13 species all of which can infect
humans.
 Two intermediate hosts
copepods of several types
fish both fresh and marine
 Many definitive hosts
carniverous animals such as bears and
dogs. Also fish eating birds

3. DIPHYLLOBOTHRIUM SP.
 Humans are also included amongst the definitive
hosts.
 Cases are increasing in recent years due to more
consumption of raw fish and importation of raw fish
from endemic areas
 Conservative estimate is 20 million cases world-wide

4. DIPHYLLOBOTHRIUM SP.

5. DIPHYLLOBOTHRIUM SP.
 Incubation period in humans is typically 4-6 weeks
but varies from 2 weeks to 2 years.
 Proglottids wider than longer may grow 1cm/hr with
tapeworm reaching 25 metres (typically 2-15
metres).
 One to several segments detach regularly releasing
immature eggs

6. DIPHYLLOBOTHRIUM SP.

7. DIPHYLLOBOTHRIUM SP
 Interventions include prevention of water
contamination ie defecating in streams and lakes by
infected locals or tourists.
 Effective screening of infected people.
 Proper handling of raw, undercooked or marinated
fish.
 Must be cooked, brined or frozen (48hrs at -18c)

8. DIPHYLLOBOTHRIUM SP.

9. DIPHYLLOBOTHRIUM SP.

10. DIPHYLLOBOTHRIUM SP.
 Presents with diarrhoea, abdo pain, vomiting, weight
loss, fatigue, constipation and discomfort.
 Severe cases may have vit B12 deficiency and
Megaloblastic anaemia.
 Large worm burdens lead to bowel obstruction.
 80% of cases may remain undetected.

11. DIPHYLLOBOTHRIUM SP.
Ova are operculate and
measure 58-75 x 40-50

12. DIPHYLLOBOTHRIUM SP.
 Treatment options include
Praziquantel 5-10mg/kg
side effects are few
Niclosamide 50mg/kg
side effects are nil

13. CASE-1
2002 - 29 MALE
 Worked as a tour guide in Alaska where he had
eaten raw Salmon.
 Proglottids measured 8mm wide by 5mm long.
 Ova were within the expected size range and were
operculated with an abopercular thickening.

14. CASE-1
2002

15. CASE-1
2002

16. CASE-2
2009-52 MALE
 Previous infestation of tapeworm.
 Tx in Jan with Praziquantel and in Dec with
Mebendazole.
 Proglottids measured 8mm wide by 4mm long.
 Ova were within the expected range and were typical
of Diphyllobothrium sp.

17. CASE-2
2009

18. CASE-2
2009

19. CASE-3
2011-58 FEMALE
 Recent change in bowel motions, constipation then
loose motions. ?tapeworm passed.
 No history of overseas travel other than Australia.
 Ate partly raw trout in new zealand (central otago)
and raw salmon in Akaroa.

20. CASE-3
 Proglottids measured 4mm wide by 3mm long.
 Ova were typical in size to the other cases and were
operculated with an abopercular thickening.

21. CASE-3

22. CASE-3

23. COMPARISON

24. COMPARISON
 It appears that each of these tapeworms are different
species especially that from case-3.
 Also the case history does not readily support a
conventional acquisition of Diphyllobothrium.
 The possibility exists that case-3 represents a New
Zealand infection.

25. SUMMARY
 Three cases of infection due to Diphyllobothryiasis
are presented.
 Each tapeworm however appears different although
broadly falls within the criteria of being wider than
longer.
 Since asymptomatic infections are more common it is
possible that further cases are present within the N.Z.
population.

26. SUMMARY
 It is possible that an indigenous fish tapeworm could
be present within New Zealands waters either in
Salmonid fish or Indigenous perch which are notable
vectors in Europe.
 Current tapeworms are being analysed for DNA
identification by Trevor and by Histology experts in
Australia.

27. AFTERMATH
 Attempts at DNA extraction have proved
unsuccessful due to preservation in formalin.
 Literature records a Japanese patient with
Diphyllobothryiasis upon return from NZ
 Studies in Australia have recorded dogs and other
small animals with various species of
Diphyllobothrium sp.

28. THE MESSAGE
 New Zealanders are at risk from acquiring tapeworm
infestation including
Fasciola hepatica ( liver fluke )
Hymenolepsis nana ( rat tapeworm )
Diphyllobothrium sp. ( fish tapeworm)
 An ova concentration is an important part of any
parasite investigation

29. THE MESSAGE
 Changes in food habits to include ever more varied
and “wild” options increase our exposure to intestinal
parasites.
 Global warming can allow the spread of intermediate
hosts and consequently the spread of intestinal
pathogens.