Malaria during pregnancy remains a serious public health problem especially in cases when there is a co-infection with Human Immunodeficiency Virus (HIV). The aim of this cross-sectional study was to determine the prevalence of malaria parasitaemia and their associated risk factors amongst HIV infected pregnant women in Sokoto State, North-Western Nigeria.
After informed consent was obtained, one hundred and three (103), HIV infected pregnant women attending antenatal clinics (ANC) participated in the study. A socio-demographic profile and risk factors of malaria was assessed from all participants. Peripheral blood samples were collected and thick blood smears were prepared and stained with Giemsa stains to check for malaria parasitaemia.
Fifty eight (56.3%) out of 103 pregnant women were infected with malaria parasites, with a mean parasite density of 700 parasites μl-1. There was no significant association between malaria parasitaemia and all sociodemographic variables and risk factors in participants (p > 0.05).
Malaria is still a major public health issue among HIV pregnant women mainly due to history of fever, illiteracy and non-compliance to using ITNs. Increasing awareness about malaria preventive measures and early focused antenatal care services will help to reduce malaria in HIV infected pregnant women and consequently, its associated morbidities and mortalities.
Prevention measures, Maternal malaria, Sokoto, Malaria prophylaxis
Malaria a tropical disease is caused by the protozoa of the genus Plasmodium species and transmitted by the female anopheles mosquito . The four etiological agents of malaria disease in humans belong to the protozoan parasites, P. falciparum, P. vivax, P. ovale, P knowlesi and P. malariae. P. falciparum is the most virulent form of the four species causing severe disease in humans. Severe malaria is a multi-system disorder, which may arise from multiple poorly understood processes including acute haemolysis of infected and uninfected RBC and dyserythropoiesis, as well as through the interaction of malaria infection with other parasite infections and with nutritional deficiencies . Malaria is well established as a major global health problem worldwide [3,4]. Malaria, Human Immunodeficiency Virus infection (HIV) and tuberculosis are among the three most important global health problems of developing countries .
Severe malaria and HIV co-infection is a disastrous syndemism especially in the face of antimalarial resistance and pregnancy. Malaria and HIV are two important global health infectious diseases. Malaria is the fourth leading cause of death of children < 5 years and pregnant women in developing Countries . Malaria cases tend to increase each year because of poor healthcare delivery systems, emergence of drug and insecticide resistance and climate changes .
Malaria and human immunodeficiency virus (HIV) infection accounted for over 3 million deaths in 2007 and millions more are adversely affected each year. Studies have shown that the co-infection exists in many parts of the world. Geographically, Malaria and HIV/AIDS co-infections overlap, primarily in sub-Saharan Africa, Southeast Asia and South America. This is particularly true in sub-Saharan Africa, where an estimated 40 million people are living with HIV and more than 350 million episodes of malaria occur yearly . There is also evidence of a negative interaction between these two infections. HIV increases the risk of malaria infection and the development of clinical malaria. Conversely, malaria increases HIV replication . Malaria and HIV infections are also the most deleterious conditions in sub-Saharan African pregnant women, in terms of the morbidity and mortality they cause in mothers and their newborns [10-16]. Nigeria has the largest population in Africa with a population of over 180 million and HIV infection prevalence of 3.17% . It is estimated that 2.95 million individuals live with HIV/AIDS in Nigeria and integrated control efforts are immeasurably needed [18,19].
HIV/AIDS can increase the adverse effects of malaria in pregnancy, including anaemia, placental malaria infection and low birth weight . HIV and malaria interact synergistically with each other. HIV infection can increase the severity of malaria and the parasite burdens might facilitate higher rates of malaria transmission. Individuals considered semi-immune to malaria in endemic regions can also develop clinical malaria if they are infected with HIV . Recent assessments propose that in malaria-endemic sub-Saharan Africa, each year approximately 25 million women become pregnant and are at increased risk of infection with Plasmodium falciparum, particularly in their first two pregnancies. This results in maternal anaemia and reduced neonatal birth weight due to preterm delivery and intrauterine growth retardation (IUGR) [21,22]. The vast majority of these infections are low-grade, frequently sub-patent [23,24] and in most women are asymptomatic and therefore undetected and untreated .
The effects of human immunodeficiency virus (HIV) on maternal health have been superimposed on that of malaria in the malaria-endemic regions. A study has it that, during pregnancy there is reduced immunity to malaria , making the pregnant women prone to severe malaria attack and subsequently anaemia. The preferential susceptibility of pregnant women may be related to some evidence that immunosuppression associated with pregnancy, occurs more in the first than subsequent pregnancies [27,28]. Previously, the depression of cell-mediated immune response to Plasmodium falciparum antigens has been implicated in this phenomenon . Epidemiological studies have shown that malaria in pregnancy is more prevalent in younger than older age groups Currently, susceptibility to malaria parasitaemia has been linked to the level of antibodies to placental sequestrated parasites . In sub-Saharan Africa, approximately 55% of the HIV-infected adults are reproductive age women accounting for 80% of the world's HIV-infected women . Studies in pregnant women suggest that in several parts of Africa the prevalence of HIV now exceeds 25% . There is paucity of data on the prevalence of malaria among HIV pregnant women in Sokoto, North Western Nigeria. The aim of this study was to investigate the prevalence of malaria parasitaemia and their associated risk factors amongst HIV infected pregnant women in Sokoto State, North-Western Nigeria.
This is a cross-sectional study carried with of 103 HIV infected pregnant women attending ante-natal clinic visit at three tertiary hospitals in Sokoto State: Specialist Hospital, Maryam Abacha Hospital and Women and children Welfare clinic in Sokoto State. The study was carried out in specialist Hospital, Sokoto State, Nigeria. Sokoto State comprises of 23 local governments. The population of the state as at the March 2006 census was 3.70 million.
The socio-demographic data and other relevant information of each participant were obtained using a structured questionnaire. Statistical data was analyzed using SPSS computer software program version 21.0. A p-value of < 0.05 was considered significant in all statistical comparisms.
The ethical clearance was obtained from the ethical committee of Sokoto state ministry of health. Informed (written) informed consent was obtained from all study subjects.
The inclusion criteria for this study included those who were positive for HIV and with febrile illnesses regardless of onset and duration of illness, those who were pregnant women and with no signs of fever, those that consented to voluntarily participate in the study while the exclusion criteria included those that did not consent to voluntarily participate, those who have started taking antimalarial drugs already, those diagnosed with leukaemia and Diabetes mellitus.
One ml of peripheral blood samples were collected through veni-puncture from all recruited HIV pregnant women and later taken to the laboratory at the Specialist Hospital for detection of malaria parasites. Using a clean grease-free microscope slide, a small drop of blood was placed to the centre of the slide, without delay, the blood was spread to make the thick smear. After drying, the slides was stained for 10-15 min with 10% Giemsa solution. When the thick film was completely dry, a drop of immersion oil was placed to an area of the film which appears mauve coloured (usually around the edges). The Slides were examined for malaria parasites and malaria pigment. At least 100 high power (× 100 objective) microscope fields were examined for parasites. A slide was considered negative when 100 high- power fields were examined under oil immersion objective. Taking the number of leucocytes per micro-litre of blood as 6,000, parasite density was expressed as: parasite count × 6,000 divided by the number of leucocytes counted as described by Adefioye, et al. .
The demographic characteristics of the one hundred and three (103) HIV pregnant women who participated in this study are summarized in Table 1, Table 2a and Table 2b. Malaria prevalence was 56.3%. Almost 50% of the participants in the study were between the age-group 25-30. The highest prevalence 71.4% was found amongst those within the age group of 37-42 while age group 19-24, 25-30, 31-36, 43-48 had prevalence 45%, 54.9%, 52.9% and 0.0% respectively (Table 1).
Table 1: Frequency distribution of sociodemographic variables of study participants. View Table 1
A higher number of participants were from household size of between 1-3 with a prevalence of 56.3%, household size of 4-6 and above 6 had prevalence of 61.1% and 40% respectively. Over 50% of the participant had just secondary education. The prevalence of malaria was higher amongst those with Islamic Education 68.1%, while in those with primary education, secondary and tertiary is 58.3%, 55.2% and 25.0% respectively. Over ¾ of participant are house wives with a prevalence of 52.5% (Table 2a). The prevalence amongst primigravidae is higher 75%, while secundigravidae is 41.2% while multigravidae had 64.5%. More than half of the participants were in their third trimesters. Prevalence of malaria seemed to be higher in the first trimester 73.1% while second and third trimesters had 56.3% and 49.2% respectively. Only one participant knew and use ART she is placed on. Amongst those who had no knowledge, there is a prevalence of 56.9%. There is a significant association between malaria and history of fever (P: 0.042). Prevalence in those with history of fever is 64.1% and those without history of fever is 43.5%. There was a prevalence of 51.6% in those who used ITNs while non-usage is 58.3%. Prevalence of Malaria amongst non-usage of Sulfadoxine/pyrimethamine is higher 57.9% than those who used Sulfadoxine/pyrimethamine (Table 2b).
Table 2A: Prevalence of Malaria parasite amongst HIV pregnant women by socio-dermographic factors. View Table 2A
Table 2B: Prevalence of Malaria parasite among HIV pregnant women by risk factors. View Table 2B
The present study has yielded some important findings in regard of malaria and HIV infections among pregnant women in Nigeria. The increased risk for severe malaria in HIV-infected persons already has been reported in some areas in Nigeria [31,32]. This present study shows 56.3% prevalence of Malaria in HIV infected a pregnant woman which is higher than a similar study conducted by Adeoti, et al.  where prevalence was (30.2%). The prevalence was also higher than compared to the prevalence (52.2%) of Malaria infection amongst apparently healthy pregnant women attending ANC in Sokoto State . The increase in prevalence may be as a result of fear of stigmatization which makes the pregnant women choose to stay at home only to avail themselves in the hospital whenever they experience high fever.
Age distribution showed that age group (37-42) years has the highest prevalence of 71.4% of pregnant women coinfected with Malaria/HIV that participated in the study, followed by age group (25-30) years with 54.9% prevalence, while age group (19-24) years has the lowest prevalence. Chi-square test showed no statistically significant association between age and coinfection of MP/HIV (P > 0.05).
The findings of this research have also demonstrated that primigravid women are more susceptible to malaria infection (75%). This corroborates the findings of Bankole, et al.  and Adefionye, et al.  in similar researches within Ebonyi, Benin City and Osogbo respectively. A possible explanation to this is that the immune system of the primigravid women may not have been previously exposed to the physiological and pathological changes in pregnancy associated with malaria. With successive pregnancies, women are exposed to variety of strains of malaria parasite, and may develop efficient mechanism to control infection and prevent the disease. Hence, women getting pregnant for the first time (primigravid) have lower immunity against strains of malaria parasite and present more frequently with malaria . The opposite is the case with women who have been pregnant before. Risk of infection reduces with increasing exposure to pregnancy resulting from acquisition of specific immunity to placental malaria arising from previous exposure. Other report associated decrease in malaria susceptibility in multiparous women to development of anti-adhesion antibodies. These anti-adhesion antibodies are believed to protect against maternal malaria by acting against chondronitin sulphate A-binding parasites. They however, develop only over successive pregnancies and as such are not present in primigravid women . Although there is no data in this study to support this assertion, Amuta, et al. . reported that mutigravid women are more informed about prevention and management methods for malaria than primigravid women, leading to reduced prevalence within the group.
Level of education may have also influenced the prevalence of malaria infection, from the study women who had only Islamic education had a higher prevalence of 68.1%, 58.3% in those with only primary education, 55.2% and 25% in those with secondary and tertiary education respectively. The study reveals also that presence of fever was a high risk factor of malaria infection.
Although the study offers some important findings, it also has limitations: The study was cross sectional and the sample size was not very large, therefore the possibility of sampling error cannot be overruled. Also, the study used ITNs as the sole indicator of control measures, but the usage of other measures such as indoor residual spraying (IRS), larvicides and mosquito repellent coils was not assessed. In addition, the non-comparison of malaria parasitaemia rate between HIV infected and HIV negative women is another limitation.
Malaria is still a major public health problem among pregnant women in Sokoto. Lack of education and non-usage of ITNs were the major factors associated with an increased risk of malaria infection. The control measures available in the area should be reviewed and emphasis should be placed on adequate sensitization on usage of ITNs. Early attendance and participation in focused ante-natal care services should be encouraged among all pregnant women especially the primigravidae, in order to reduce the risk of malaria infection in pregnancy. Again, awareness on malaria prevention measures during pregnancy should target young women even before marriage preferably at schools, and social and religious gatherings.