Effect of Seasonality and Ecological Factors on the Prevalence of the Four Malaria Parasite Species in Northern Mali

Table 3

Malaria infection prevalence and morbidity in May 2004 and February 2005.

	May 2004		February 2005		𝑃 value (Fisher and χ ^2 tests)
Plasmodium specie frequencies	N (%)	Total	N (%)	Total
P. falciparum	50 (74.13)	64	56 (63.72)	97	0.0124*
P. malariae	6 (9.38)	64	21 (22.54)	97	0.0419 *
P. ovale	2 (3.13)	64	2 (2.06)	97	0. 9258
P. vivax	5 (7.81)	64	10 (10.31)	97	>0.9999
P. falciparum + P. malariae	1 (1.56)	64	7 (7.21)	97	0.2060
P. falciparum + P. vivax + P. ovale	0 (0)	64	1 (1.03)	97	N/A
Malaria infection and morbidity
Plasmodic Index	64 (4.95)	1293	100 (7.06)	1415	0.0259 *
Gametocytic Index	6 (0.46)	1293	13 (0.91)	1415	0.2364
Anemia	110 (8.50)	1293	106 (7.49)	1415	0. 3660
Fever	308 (23.82)	1293	310 (21.90)	1415	0. 2557
Splenomegaly	64 (4.94)	1293	41 (2.89)	1415	0. 0077*
Overall malaria symptoms	42 (3.24)	1293	343 (24.24)	1415	<0. 000001 *

*Significant 𝑃value.
Plasmodium falciparum species decreased significantly in February (𝑃=0.0124); in contrast, there was a marked increased in the frequency P. malariae in February (𝑃=0.0419). P. ovale and P. vivax remained stable between May 2004 and February 2005 (Fisher’s exact test, 𝑃>0.05). Plasmodic index increased remarkably in February 2005 (𝑃=0.0259); in contrast, the gametocytic index did not vary significantly between March and February but increased in February (𝑃=0.2364). Symptoms such as anemia and fever did not vary significantly between March and February (𝑃>0.05). Splenomegaly decreased significantly in February 2005 (𝑃<0.000001).