Cluster analysis of the clinical histories of cattle affected with bovine anaemia associated with Theileria orientalis Ikeda type infection

• Published in: New Zealand veterinary journal 2017-11, Vol.65 (6), p.305-312
• Main Authors: Lawrence, KE, Forsyth, SF, Vaatstra, BL, McFadden, AMJ, Pulford, DJ, Govindaraju, K, Pomroy, WE
• Format: Article
• Language: English
• Subjects: Anemia - epidemiology; Anemia - parasitology; Anemia - veterinary; Animals; bovine; Cattle; Cattle Diseases - epidemiology; Cattle Diseases - parasitology; clinical history; Cluster Analysis; correspondence analysis; Epidemiological Monitoring; Female; Ikeda type; Milk; surveillance; Theileria; Theileria orientalis; Theileriasis - epidemiology; Theileriasis - parasitology
• ISSN: 0048-0169; 1176-0710
• DOI: 10.1080/00480169.2017.1364180

To determine the most commonly used words in the clinical histories of animals naturally infected with Theileria orientalis Ikeda type; whether these words differed between cases categorised by age, farm type or haematocrit (HCT), and if there was any clustering of the common words in relation to these categories. Clinical histories were transcribed for 605 cases of bovine anaemia associated with T. orientalis (TABA), that were submitted to laboratories with blood samples which tested positive for T. orientalis Ikeda type infection by PCR analysis, between October 2012 and November 2014. χ 2 tests were used to determine whether the proportion of submissions for each word was similar across the categories of HCT (normal, moderate anaemia or severe anaemia), farm type (dairy or beef) and age (young or old). Correspondence analysis (CA) was carried out on a contingency table of the frequency of the 28 most commonly used history words, cross-tabulated by age categories (young, old or unknown). Agglomerative hierarchical clustering, using Ward's method, was then performed on the coordinates from the correspondence analysis. The six most commonly used history words were jaundice (204/605), lethargic (162/605), pale mucous membranes (161/605), cow (151/605), anaemia (147/605), and off milk (115/605). The proportion of cases with some history words differed between categories of age, farm type and HCT. The cluster analysis indicated that the recorded history words were grouped in two main clusters. The first included the words weight loss, tachycardia, pale mucous membranes, anaemia, lethargic and thin, and was associated with adult (p