Top Papers in Neglected Tropical Diseases Diagnosis

Top papers in Neglected Tropical Diseases

Diagnosis

Professor Peter L Chiodini ESCMID eLibrary © by author Neglected tropical diseases http://www.who.int/neglected_diseases/diseases/en/ Accessed 9th April 2017

• Buruli ulcer • Lymphatic filariasis • Chagas disease • Mycetoma • Dengue and Chikungunya • Onchocerciasis • Dracunculiasis • Rabies • Echinococcosis • Schistosomiasis • Foodborne • Soil-transmitted trematodiases helminthiases • Human African • Taeniasis/Cysticercosis trypanosomiasis • Trachoma • Leishmaniasis • Yaws • ESCMIDLeprosy eLibrary © by author PLOS Neglected Tropical Diseases http://journals.plos.org/plosntds/s/journal-information#loc-scope Accessed 9th April 2017 The “big three” diseases, HIV/AIDS, malaria, and tuberculosis, are not generally considered for PLOS Neglected Tropical Diseases.

Plasmodium vivax possibly ESCMID eLibrary © by author Flynn, FV (1985)

“As is your pathology, so is your practice”

ESCMID eLibrary © by author Time for a Model List of Essential Diagnostics Schroeder LF et al. NEJM 2016; 374: 2511

ESCMID eLibrary © by author Peruvian Leishmania: braziliensis or mexicana?

ESCMID eLibrary © by author Leishmania (Viannia) from Peru

ESCMID eLibrary © by author Karimkhani C et al. Lancet Infect Dis 2016; 16: 584-591

• Global Burden of Disease Study

“Unlike the incidence of most other neglected tropical diseases, the incidence of cutaneous leishmaniasis is increasing”

ESCMID eLibrary © by author Karimkhani C et al. Lancet Infect Dis 2016; 16: 584-591

ESCMID eLibrary © by author Akhoundi M et al. Molecular Aspects of Medicine (2017) doi: 10.1016/ j.mam.2016.11.012.

ESCMID eLibrary © by author So PCR solves the problem of Leishmania diagnosis and species identification

Really?

ESCMID eLibrary © by author Comparison of Leishmania typing results obtained from 16 European clinical laboratories Van der Auwera G et al. Euro Surveill. 2016 Dec 8;21(49). pii: 30418.

• 21 Leishmania strains (18 Montpellier; 3 Antwerp) • Characterized by: • Multi-locus enzyme electrophoresis • Multi-locus sequence analysis • Amplified fragment length polymorphism • Whole genome sequencing • DNA extracted from parasite cultures • Samples aliquoted to 50 µL of 10 ng/ µL and coded • Typed by 16 laboratories in 12 countries ESCMID• 10 Europe; 1 Israel; 1 Turkey eLibrary © by author ESCMID eLibrary © by author ESCMID eLibrary © by author Conclusions Van der Auwera G et al. Euro Surveill. 2016 Dec 8;21(49). pii: 30418.

• Treatment choice is heavily influenced by the infecting species • But despite being reference laboratories, only 8 made no errors • Typing errors on 5.9% Old World strains; 9.6% new World strains • All received pure parasite DNA • Typing success expected to be lower on clinical samples • But will have travel history ESCMID eLibrary © by author Conclusions Van der Auwera G et al. Euro Surveill. 2016 Dec 8;21(49). pii: 30418.

• hsp70 and the miniexon currently the best typing tools • Use of ITS1 should be restricted to the Old World • Designed for those strains; only the L. (Leishmania) subgenus there • Considerable room for improvement and standardisation • For this to happen you will need • Well validated (ESCMID?) SOPs for: • Testing • Interpretation • Reporting (one error even in this study) • ESCMID (ESGCP) funded ESCMID• 10,000 Euros can make a big difference eLibrary © by author Adult Ascaris Worms

ESCMID eLibrary © by author A. lumbricoides or A. suum?

Ascaris suum is present at slaughter Zoonotic Ascariasis in Cornwall in 3.4 to 6.5% of British pigs Bendall et al EID 2011. 17: 1964-6 Sanchez-Vazquez et al Vet Parasitol 2010; 173: 271-9 • Cornwall 0.87 per 100,000 Rest of England 0.12 • Pig holding within same postcode OR 4.65 p = 0.036 • 11 Ascaris from humans in Cornwall genotyped • All had pig-like DNA ESCMIDSaddleback Sow eLibrarysequences © by author Ascaris lumbricoides vs Ascaris suum da Silva Alves et al JID 2016: 213, 1355

• Life cycle of Ascaris from humans or from pigs can be completed in both hosts

• Cross-transmission takes place

• There are Ascaris genotypes common to both hosts ESCMID eLibrary © by author Molecular Epidemiology of Ascariasis Betson et al (2014) JID 210: 932-941

• Resource-rich countries • Human Ascaris infections predominately of pig origin • Resource-poor countries • Uganda (18% of households keep pigs) • 0.7% human worms of pig origin • 1.8% pig worms of human origin • China • 13.9% human worms zoonotic • 0.8% pig worms anthroponotic • 7.8% hybrids ESCMID eLibrary © by author Ascaris from Humans and Pigs Appear to Be Reproductively Isolated Species Søe MJ et al. PLoS Negl Trop Dis 2016. 10(9): e0004855. doi:10.1371/journal.pntd.0004855 • Conflicting results from Nuclear DNA Markers • A single host shift between pigs and humans was not demonstrated, suggesting that host-associated populations emerged after geographical isolation • Worms segregated first by host and then by geographic location, with significant genetic differentiation between populations.

• Hybrids appear unfertile, indicating reproductive isolation

• The answer may come from comparative genomic studies of Ascaris populations using next-generation sequencing ESCMID eLibrary © by author Ascaris lumbricoides or Ascaris suum: What′s in a Name? Betson &Stothard J Infect Dis 2016 213 (8): 1355-1356

• Ascaris lumbricoides vs Ascaris suum depends on the species definition used: • Based on a phenetic species concept, they would belong to the same species • Based on a biological species concept, it could be argued that they comprise 2 separate species • Confirmation of this would entail experimental crosses • Why does it matter? • Effects on control and elimination • Gene flow between worms infecting different hosts could favour ESCMIDthe spread of anthelmintic resistance eLibrary © by author Implications for control programmes Betson et al (2014) JID 210: 932-941

• Control depends heavily on periodic treatment of preschool and school-aged children in Ascaris-endemic communities

• “Where it is common for households to keep pigs and/or where pig manure is used as a fertilizer ……. progress …may be hampered if there is significant cross-over of transmission”

• “Should be taken into account by mathematical models” ESCMID eLibrary © by author Some headlines

ESCMID eLibrary © by author Card Agglutination Test for Trypanosomiasis (CATT) Used to detect T. b. gambiense since 1978

ESCMID eLibrary © by author RDT for T. b. gambiense Bisser S et al. PLoS Negl Trop Dis. 2016 Apr 8;10(4):e0004608

ESCMID eLibrary © by author RDT for T. b. gambiense Bisser S et al. PLoS Negl Trop Dis. 2016 Apr 8;10(4):e0004608 n = 149 HAT cases Sensitivity (%) Specificity (%)

Prototype RDT 89.26 94.58 (used alone would have missed 16 cases)

CATT whole blood 93.96 95.91 (used alone would have missed 9 cases) CATT 1 in 8 89.26 98.88 ESCMID eLibrary © by author Strongyloides rhabditiform larva

ESCMID eLibrary © by author StrongNet: An International Network to Improve Diagnostics and Access to Treatment for Strongyloidiasis Control. Albonico M et al. PLoS Negl Trop Dis 2016. 10(9): e0004898. doi:10.1371/journal.pntd.0004898

• “Not officially listed as a neglected tropical disease, strongyloidiasis stands out as particularly overlooked”

• Expert consensus guidelines for screening and follow-up of at-risk individuals • See http://www.cohemi-project.eu/

• Stool-based rapid diagnostic test (RDT) for S. stercoralis antigen is required • Under development; see http://www.nidiag.org/ ESCMID eLibrary © by author Diagnosis of Strongyloides stercoralis: Detection of parasite-derived DNA in urine Lodh et al. Acta Tropica 2016. 163: 9–13

ESCMID eLibrary © by author Colorimetric Detection of Plasmodium vivax in Urine Using MSP10 Oligonucleotides and Gold Nanoparticles. Alnasser et al. PLoS Negl Trop Dis 2016. 10(10): e0005029. doi:10.1371/journal.pntd.0005029

ESCMID eLibrary © by author Coulibaly et al. Accuracy of Mobile Phone and Handheld Light Microscopy for the Diagnosis of Schistosomiasis and Intestinal Protozoa Infections in Côte d’Ivoire. PLoS Negl Trop Dis 2016. 10(6): e0004768.

1998 • England was the first non-endemic country to screen at-risk blood donors for Trypanosoma cruzi infection

2017 • The UK still has no systematic programme to screen at-risk pregnant women for this infection • Compare this with Zika virus • A pilot Chagas antenatal screening project will commence this year in London ESCMID eLibrary © by author Development of Diagnostics for Chagas Disease: Where Should We Put Our Limited Resources? Picado et al. (2017) PLoS Negl Trop Dis 2017. 11(1): e0005148. doi:10.1371/journal.pntd.0005148

Less than 1% of the 6 to 7 million people infected with Trypanosoma cruzi are treated

ESCMID eLibrary © by author Development of Diagnostics for Chagas Disease: Where Should We Put Our Limited Resources? Picado et al. (2017) PLoS Negl Trop Dis 2017. 11(1): e0005148. doi:10.1371/journal.pntd.0005148

Still time to take part in this survey

• There is no room at all for complacency • The NTDs are still neglected

• But low cost, effective and quality-assured diagnostics can be applied to these diseases and have a major impact • Malaria RDTs are the best example, but many diseases have none

• External Quality Assessment Schemes are essential for credible diagnostics provision ESCMID• Including those provided by ReferenceeLibrary Laboratories © by author http://www.thehtd.org/