Walter T. Johnson (1892 to 1937): pioneer of coccidiosis research in the fowl

Figures & data

Figure 1. Photograph of Johnson reproduced from KOAC Radio Programs, 1925/1926 (Anonymous, 1926a).

Figure 2. Unsporulated and sporulated oocyst of (2a) E. acervulina, (2b) E. mitis, (2c) E. praecox (Johnson, 1938).

Figure 3. Unsporulated and sporulated oocyst of (3a) E. maxima, (3b) E. tenella, (3c) E. necatrix (Johnson, 1938).

Table 1. Measurements of oocysts of Eimeria species

		Dimensions (width×length [μm])
Species	Shape index^a	Minimum^b	Maximum^b	Average^b	Average^c
E. acervulina	0.77	12.0×14.0	14.8×20.0	13.8×18.0	14.3×19.5
E. mitis	0.91	12.0×13.0	16.0×18.0	13.7×15.0	15.5×16.2
E. praecox	0.87	19.0×22.0	22.0×25.0	20.6×23.8	17.1×21.3
E. maxima	0.75	20.0×26.4	27.6×36.0	22.9×30.4	22.6×29.3
E. tenella	0.74	15.0×20.0	19.4×25.0	17.5×23.7	19.0×22.6
^a Shape index of Johnson's strains obtained by dividing average width by length.
^b From Johnson (1938).
^c From Tyzzer (1929) and Tyzzer et al. (1932).

Anonymous 1926a KOAC Radio programs 1925–26 Extension Bulletin 387 pp. 5–35 Corvallis OR Oregon Agricultural College Extension Service

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Johnson WT 1938 Coccidiosis of the Chicken with Special Reference to Species Station Bulletin 358 pp. 2–18 Corvallis OR Agricultural Experiment Station, Oregon State College

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Tyzzer , EE , Theiler , H and Jones , EE . 1932 . Coccidiosis in gallinaceous birds II. A comparative study of species of Eimeria of the chicken . American Journal of Hygiene , 15 : 319 – 393 .

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