Malaria Prevalence among Pregnant Women in Relation to Parity, Gestation Period and Age in Gombe, North Eastern Nigeria

: This study was conducted in order to determine malaria prevalence in relation to parity, gestational period and age of the pregnant women in Gombe, Nigeria. Three hundred and eighty four (384) pregnant women who registered for antenatal care in five randomly selected health care facilities (Tudun Wada Primary Health Care, Idi Health Clinic, Madaki Health Clinic, Pantami Primary Health Care And Gombe Town Maternity) residing within Gombe Local Government Area, Gombe State, Nigeria, constituted the study population. Five (5) ml of the maternal peripheral blood was obtained from each participant by the use of a sterile syringe and placed in a sterile Ethylene Diamine Tetraacetic Acid (EDTA) container for laboratory analysis. The malaria parasite was detected by microscopic examination of Giemsa-stained thick blood films. A high prevalence of 78.4% was observed among the studied population, with the primigravidae having higher prevalence (87.8%) than the multigravidae (73.6%). Women in second trimester recorded the highest prevalence (81.6%) followed by those in third trimester (76.4%), then the first trimester (68.4%). In relation to age, younger women (17 – 20 years) had the highest prevalence (88.4%) of malaria parasitaemia followed by 21-25 years category (79.1%), while those above 25years had the lowest prevalence (67.7%).significant association between age and malaria infection was established. The vulnerable age group need to be cautious of their exposure to mosquitoes’ bites so as to reduce the pressure on the already overstretched health facilities.

Malaria infection is a major public health problem in sub-Saharan Africa, especially in pregnancy due to its association with poor fetal and maternal outcomes (Sule-Odu et al., 2002;Omo-Aghoja et al., 2008). The parasites are transmitted from the blood of an infected host to the blood of an uninfected person through bite (inoculative method) by female Anopheles mosquito. There are five species of Plasmodium that can infect human, these are; Plasmodium malariae, Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, and Plasmodium knowlesi (Foster et al., 2014).
The burden of malaria infection during pregnancy is caused mainly by Plasmodium falciparum the most common species in Africa (Alaku et al., 2015). Malaria in pregnancy is a health problem requiring multidisciplinary and multidimensional solutions. Pregnant women constitute the main adult risk group for malaria and 80% of death due to malaria in Africa occurs in pregnant women and children below 5 years (Abe and Olusi, 2011;Nwaorgu and Orajaka, 2011). In malaria transmission areas, pregnant women, in particular primigravidae, are known to be susceptible to malaria and to have higher prevalence and densities of parasitaemia than are non-pregnant women from the same population (Desai et al., 2007) The risk varies with the age of the pregnant woman, possibly due to cumulative exposure to malaria over a lifetime, and with parity, as a result of pregnancy-specific immunity acquired after exposure to malaria in previous pregnancies.
The consequences of malaria infection during pregnancy will depend on maternal malaria immune status; however, infections are associated with maternal anaemia and fetal growth retardation, and can result in acute illness, pregnancy loss or preterm delivery, and even maternal mortality.

MATERIALS AND METHODS
Study Area: The research was conducted in six randomly selected wards out of 11 wards in Gombe Local Government Area, Gombe State Capital. Gombe Local Government Area is situated at Latitude 10 0 17' N and Longitude 11 0 10' E with an altitude of 500 M above sea level. The Local Government Area has a total population figure of 250,000 (National Population Census, 2006 Ethical Consideration: A written approval to conduct the study was granted by the authority concerned after which study participants were informed on the research and its purpose, and their consent was obtained for participation in the study before sample collection. Blood Sample Collection: Five (5) ml of the maternal peripheral blood was obtained from each participant by use of a sterile syringe and placed in a sterile Ethylene Diamine Tetraacetic Acid (EDTA) container for laboratory analysis as described (Cheesbrough, 2009). The blood sample was collected with the help of a qualified and certified laboratory scientist recruited for the study.

Parasitological and Haematological Tests: Malaria
Parasite Screening: The malaria parasite was detected by microscopic examination of Giemsa stained thick blood films. The parasitaemia was expressed as number of malaria parasite per microlitre of blood.
Thick Blood Film Preparation: A thick blood smear was prepared by spreading a drop of blood placed on the centre of a clean grease free slide. This was allowed to air-dry for ten minutes. It was then rinsed under tap water, air-dried and a drop of immersion oil placed on it for examination with x100 objectives (Cheesbrough, 2009).
Parasite identification: Positive slides were identified and interpreted on the basis of microscopy by using standard method described (Cheesbrough, 2009). with only 13 individuals that tested positive out of the 19 individuals examined. The age of the study participants ranged from 17-40 years, this was categorized into three different mutually exclusive categories. The lowest category is 17-20 years consisting of 121 (31.5%) study participants, followed by the middle category 21-25 years represented by 139 (36.2%) the last category, 26 years and above, comprises of 124 (32.3%). Table 1 revealed that 17-20 years age category had the highest malaria prevalence (88.4%) which was found to be statistically significant (p<0.05) when compared with the other two groups. The lowest prevalence recorded was from 26 years and above category (67.7%). The result of this study demonstrated 78.4% malaria prevalence among the pregnant women in the study area. This prevalence is higher than the 52.7% malaria prevalence reported (Amadi and Nwankwo, 2012) in Abia. The malaria prevalence is lower than 99% prevalence reported in Enugu (Gunn et al., 2015). It is also lower than the 89 % affected in Ibadan (Falade et al., 2008) but similar to 78.9% reported (Oladeinde et al., 2012) in Benin and 72% documented (Adefioye et al., 2007) in south west.

RESULTS AND DISCUSSION
However the malaria prevalence obtained in this study could be considered high knowing that malaria prevalence is higher in the southern part of the country than their northern counterparts (FMoH, 2010) and all the prevalences used in the comparison above are from the Southern Region. The high malaria prevalence could be attributed to the environmental conditions (especially during the rainy season which corresponded to the period the study was carried out) inherent in the study area creating conducive atmosphere for the breeding of mosquitoe vectors.  Malaria (X²Cal=6.2,X²tab=5.99,df =2,p= P>0.05) Not significant. PARASITAEMIA (X²Cal=6.53,X²tab=12.59,df = 6,p= P>0.05) Not significant *b Malaria (X²Cal=2.32,X²tab=5.99,df =2,p= P>0.05) Not significant. PARASITAEMIA (X²Cal=4.25,X²tab=12.59,df = 6,p= P>0.05) Not significant *c Malaria (X²Cal=13.19,X²tab=5.99,df = 2,P<0.05) significant. PARASITAEMIA (X²Cal=18.65,X²tab=12.59,df = 6,P<0.05) significant Malaria Prevalence in Relation to parity Gestational period and Age: The finding that primigravida had the higher prevalence than the multigravida have earlier been documented (Singh et al 1999;Tayo et al., 2009;Amali, et al, 2011) showed that malaria is more common in primigravida than in multigravida. This is because in a place where transmission is high and acquired pregnancy immunity is expected to be significant, primigravida are the most vulnerable group. On the other hand, the result is in contrast to the findings (Simon-Oke et al, 2015) where multigravidae had higher prevalence than primigravida. Pregnant women in second and third trimesters had higher levels of parasitaemia. This is in line with the previous findings (Menendez et al., 1995) but in conflict with the work Brabin, (1999) who reported that pregnant women were at higher risk during the first trimester of pregnancy. Younger pregnant women were more affected by the malaria than the older ones in this study. This was in conformity with the earlier findings (Odoula et al., 1992;Bouyou-Akotet et al., 2003: Rogerson et al., 2008. They showed that higher prevalence of malaria at lower age group and lower prevalence at higher age groups might be due to the existence of natural immunity to infectious diseases (malaria inclusive) which the pregnant women acquired as their ages increased. Falade et al., (2008) however reported no significant difference between malaria infection and maternal age. Malaria prevalence was found to be higher in pregnant women who were less than 20 years old and were in their second trimester of pregnancy and are primigravidae. There was no statistically significant association (p<0.05) between parity and gestational period on one hand and malaria infection on the other hand, while significant association between age and malaria infection was established. It is therefore pertinent to note that the pregnant women who are less than 20 years old, are vulnerable age group and should be cautious of their exposures to mosquitoes' bites so as to reduce the pressure on the already overstretched health facilities.