Susceptible trichostrongyloid species mask presence of benzimidazole-resistant Haemonchus contortus in cattle

Parasites & Vectors

Table 5 Mutations in codon 198 in isotype 1 β-tubulin gene of Haemonchus spp. collected from cattle in five different study areas in South Darfur State, Sudan, detected by Sanger sequencing

Study area	Source of samples	Type of samples^a	Sample collection day^b	Haemonchus spp.	No.^c	No. of samples with each variant
						GAA	TTA	GTA	TAA
Beleil	Trial	L3	0	H. placei	0	0	0	0	0
				H. contortus	0	0	0	0	0
				Mixed infections^d	1	1	0	0	0
			14	^e	–	–	–	–	–
Kass	Trial	L3	0	H. placei	4	4	0	0	0
				H. contortus	0	0	0	0	0
				Mixed infections^d	1	0	1	0	0
			14	H. contortus	1	0	1	0	0
Nyala	Trial	L3	0	H. placei	1	1	0	0	0
				H. contortus	0	0	0	0	0
				Mixed infections^d	5	2	1	2	0
			14	H. contortus	2	0	2	0	0
	Abattoir	Adult	n.a.	H. placei	2	2	0	0	0
				Mixed infections^d	1	1	0	0	0
Rehed Al-Birdi	Trial	L3	0	H. placei	0	0	0	0	0
				H. contortus	6	6	0	0	0
				Mixed infections^d	4	4	0	0	0
			14	H. contortus	4	0	4	0	0
	Abattoir	Adult	n.a.	H. placei	3	3	0	0	0
				Mixed infections^d	1	1	0	0	0
Tulus	Trial	L3	0	H. placei	0	0	0	0	0
				H. contortus	2	1	0	0	1
				Mixed infections^d	3	2	1	0	0
			14	H. contortus	6	0	6	0	0
	Abattoir	Adult	n.a.	H. placei	7	7	0	0	0
				Mixed infections^d	4	4	0	0	0
Total (and %)				H. placei	17	17 (100)	0 (0)	0 (0)	0 (0)
				H. contortus	21	7 (33)	13 (62)	0 (0)	1 (5)
				Mixed infections^d	20	15 (75)	3 (15)	2 (10)	0 (0)
				All the samples	58	39 (67)	16 (28)	2 (4)	1 (2)

n.a., samples collected from cattle abomasa at abattoirs with unknown history of anthelmintic treatments
^aPools of third-stage larvae (L3) of at least ⁓ 1000 gastrointestinal nematode L3/sample or of adult male Haemonchus spp. isolated from cattle abomasa at abattoirs (16–100 worm/sample)
^bFaecal samples were collected before treatment (day 0) and on day 14 after albendazole treatment at dose of 7.5 mg/kg body weight
^cNumber of pools tested
^dMixed infections with Haemonchus placei/Haemonchus contortus that identified in pools of L3 or adults based on chromatograms of the isotype 1 β-tubulin gene as described by Fávero et al. (submitted)
^eNo nematode eggs detected on day 14 of albendazole treatment (FECR: 99.9%). Therefore, faecal cultures were not prepared

ISSN: 1756-3305