Lucas Cunningham Research September 2014

The little pigs and the big bad trypanosome

Lucas J Cunningham 1

African Trypanosomiasis (Sleeping Sickness) • • • • • •

Neglected Tropical Diseases, fatal if untreated 66 million people at risk in 36 African countries Single cell parasites called trypanosomes Transmitted by the bite of a tsetse fly Causes serious disease in animals Animal African Trypanosomiasis is responsible for a loss of U.S. $4.5 billion per year across sub Saharan Africa

http://sitemaker.umich.edu/section003group6/impact_on_food_production_and_security http://news.sciencemag.org/chemistry/2011/06/hitting-sleeping-sickness-where-it-lives

https://microbewiki.kenyon.edu/index.php/Membrane_proteins_as_mechanisms_of_immune_syste 2 m_evasion_in_Trypanosoma_brucei http://www.raywilsonbirdphotography.co.uk/Galleries/Invertebrates/vectors/Tsetse_Fly.html

Importance of Human African Trypanosomiasis (HAT)

Elimination 2020

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African Trypanosomiasis There are three species in the brucei group • Trypanosoma brucei gambiense

• Trypanosoma brucei rhodesiense South Sudan

Gambiense (chronic) sleeping sickness

• Trypanosoma brucei brucei

Rhodesiense (acute) sleeping sickness Images: http://www.lib.utexas.edu/maps/africa.html

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Can animals be a reservoir for gambiense? • Past experiments have shown that pigs can be readily infected with gambiense sleeping sickness • Recently more importance has been placed on the possibility of animal reservoirs influencing the transmission of the disease

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South Sudan

Pig Sampling in Uganda 366

DRC Gambiense sleeping400 sickness

Rhodesiense sleeping sickness

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Pig sampling method

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Analysis of pig blood for trypanosomes General test for species of interest

Specific tests for species

• Highly sensitive • Targets an area of DNA with 10,000 copies per parasite

• limited • Targets an area of DNA with 1 copy per parasite

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Results • 766 pigs were screened with the general test

Moyo

Arua

Site Wiliffi Duku Tondolo Ngalabia Muttee Drimveni Inia Perego Opiro Moipi Kendi Goopi Kuleni

Total pigs 67 45 25 68 51 100 44 37 109 67 113 32 8 766

Infected 1 1 0 0 7 3 13 0 0 0 0 0 0 25

% infected 1.49 2.22 0.00 0.00 13.73 3.00 29.55 0.00 0.00 0.00 0.00 0.00 0.00 3.26

3.26% infection of T. brucei sl overall 25 out of 400 were infected, 6.25% in Arua

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Map

29.6 3.0 2.2 13.7 1.5

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Do we have the big bad trypanosome? • 25 positive samples re-screened for gambiense infections • So far none of the pigs appear to be positive for the big bad trypanosome, this could be good news for the farmers

• But… • Not all the tests have been finished, issue with sensitivity, plus the pigs still have animal trypanosomiasis 11

Conclusions • • • • • •

25 out of 766 pigs positive for trypanosomes of interest 20 out of 25 cases came from just two sample sites The issue with the sensitivity needs to be ruled out Secondary tests will need to follow to determine exact species present Why is Arua a hot spot and why isn’t Moyo? Is the big bad trypanosome still at large, not yet concluded

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Thanks to: • • • • • • • • • •

Stephen Torr (LSTM and Warwick NTD) Jessica Lingley (LSTM, Vector Group) Ugandan field technicians Ugandan vets Ugandan farmers Lee Haines (LSTM, Vector Group) Johan Esterhuizen (LSTM, Vector Group) Inaki Tirados (LSTM, NTD) Hannah Betts (LSTM, Vector Group) Liam Morrison (Roslin Institute, University of Edinburgh)

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Impact of finding gambiense in pigs • Target and screen animals- requires more accurate field diagnostics • Identifying areas of transmission- disease is very focal, mass screening of the flies for the parasite maybe in conjunction with human and animal screening • Integration of controls- will probably require a number of control strategies to eliminate the disease • Disease eradication challenging

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