Recurrent headaches may be caused by cerebral toxoplasmosis

Table 1 Demographic data and positive serum anti-Toxoplasma gondii IgG concentrations in 19 of 178 children hospitalized because of recurrent headaches

Pt	Age/sex	Living place	Contact with animals1	Serum anti-Toxo IgG concn (n ≤9 IU/mL)	Avidity index2
1	8/M	Town	Yes1	205.5	0.750
2	9/M	Town	Yes1	59.5	0.754
3	9/F	Town	Cat	59.0	0.202
4	12/F	Town	Cat	94.1	0.666
5	13/F	Town	No	168.0	0.782
6	13/F	Town	Yes1	83.0	0.800
7	13/F	Town	No	123.9	0.861
8	14/F	Village	Yes1	151.2	0.740
9	15/M	Town	Yes1	231.4	0.670
10	16/F	Town	Yes1	81.0	0.859
11	16/F	Town	Dog	74.7	0.767
12	16/M	Town	Ferret	165.7	0.778
13	17/M	Village	Yes1	175.03	0.788
14	17/F	Town	Yes1	145.0	0.772
15	17/F	Town	Yes1	40.5	0.687
16	17/M	Town	Yes1	> 240.0	0.843
17	17/F	Village	Yes1	71.7	0.925
18	17/M	Town	Dog, parrot	32.2	0.796
19	17/M	Village	Dog, cat, hens, ducks, cows	82.0	0.894

¹Dog, cat and/or turtle.

²Avidity index: < 0.4-low avidity, 0.4 to 0.5-moderate, and ≥ 0.5-high avidity. In Pt 13 control serum anti-Toxo IgG concentration examined 9 mo later was 552.7 IU/mL. It must be noted that Toxoplasma gondii IgG and IgA, but not IgM, antibody titers were also found to be increased in sera of immunocompetent mice in association with proliferation of tachyzoites in the brain during the chronic stage of infection[17].