Egg hatch assay

Egg hatch assay (EHA), also called an egg hatch test (EHT),{{Cite journal|last1=von Samson-Himmelstjerna|first1=Georg|last2=Coles|first2=Gerald C.|last3=Jackson|first3=Frank|last4=Bauer|first4=Christian|last5=Borgsteede|first5=Fred|last6=Cirak|first6=Veli Y.|last7=Demeler|first7=Janina|last8=Donnan|first8=Alison|last9=Dorny|first9=Pierre|date=2009-05-12|title=Standardization of the egg hatch test for the detection of benzimidazole resistance in parasitic nematodes|journal=Parasitology Research|language=en|volume=105|issue=3|pages=825–834|doi=10.1007/s00436-009-1466-1|pmid=19452165|s2cid=21286130|issn=0932-0113|url=http://edepot.wur.nl/108571|url-access=subscription}} is a method used to determine a given parasite's resistance to extant drug therapy.{{Cite journal|date=2014-06-16|title=Development of an egg hatch assay for the detection of anthelmintic resistance to albendazole in Fasciola hepatica isolated from sheep|journal=Veterinary Parasitology|language=en|volume=203|issue=1–2|pages=217–221|doi=10.1016/j.vetpar.2013.11.020|pmid=24576602|issn=0304-4017|last1=Robles-Pérez|first1=D.|last2=Martínez-Pérez|first2=J.M.|last3=Rojo-Vázquez|first3=F.A.|last4=Martínez-Valladares|first4=M.|hdl=10261/99726}}{{Cite journal|last1=Albonico|first1=Marco|last2=Wright|first2=Victoria|last3=Ramsan|first3=Mahdi|last4=Haji|first4=Hamadi J.|last5=Taylor|first5=Martin|last6=Savioli|first6=Lorenzo|last7=Bickle|first7=Quentin|date=June 2005|title=Development of the egg hatch assay for detection of anthelminthic resistance in human hookworms|journal=International Journal for Parasitology|volume=35|issue=7|pages=803–811|doi=10.1016/j.ijpara.2005.02.016|issn=0020-7519|pmid=15885696}}

Fresh eggs are incubated from the parasite of interest and serial dilutions of the drug of interest are applied. The percentage of eggs that hatch or die is determined at each concentration and a drug response curve may be plotted. The data can then be transformed and analysed to give further statistics such as an effective dose.

This technique is labour-intensive, expensive and can take some time, but an egg hatch assay will give an accurate and reliable result.{{Cite book|url=https://books.google.com/books?id=-nS2JylUCCEC&dq=%22Egg+hatch+assay%22+definition&pg=PA174|title=Sheep Flock Health: A Planned Approach|last=Sargison|first=Neil|date=2009-01-26|publisher=John Wiley & Sons|isbn=9781444302608|language=en}}