An attempt was made to identify the human hookworm involved in failed-treatment cases using abnormal hosts and scanning electron microscopy. Thirty-seven, 2 to 6 month old Chinese hamsters (Cricetulus griseus) from a closed, outbred, conventional colony, were each given between 20 and 120 filariform larvae per os. The larvae were cultured from faeces from mebendazole (Vermox®) 500 mg single-dose, failed-treatment cases living in the lowveld farming area of the Transvaal Province, South Africa. About 60 to 78 days after inoculation, the animals were killed and adult worms were removed from their small intestines. Eleven (30%) of the 37 hamsters harboured a total of 31 adult worms (19 males and 12 females), while 26 hamsters were refractory to infection. The greatest number of worms recovered from a single animal was six. A total of 27 worms (17 males and 10 females) were subjected to examination by scanning electron microscopy. Micrographs showed male and female worms to be morphologically all of the Necator americanus species, as identified by a pair of ventral and dorsal cutting plates, a dorsal tooth and the fused terminus of spicules in the male bursa. The transverse cuticular striations were distinct and smooth. Several points of interest arose from the results of this study and are discussed.

Cognitive behaviour therapy (CBT) treatments have been developed and validated with respect to specific diagnoses. In routine clinical practice diagnostic accuracy is poor, making for poorly targeted treatment. The problems posed by lack of diagnostic rigour, including non-detection of co-morbidity, are rarely the subject of supervision sessions and treatment failures may be inappropriately attributed to other factors such as lack of therapeutic skill or an unmotivated client. It is argued that a false dichotomy exists between diagnosis and case formulation fuelled by professional territorial disputes. We suggest that diagnosis acts as a lens, focusing attention on the range of cognitions salient to a case formulation and also highlights psychosocial and environmental factors that may affect treatment outcome. It is recommended that practitioners enhance their effectiveness by using structured interviews routinely as a part of their ongoing assessment of clients.