Malaria in the New-born as Seen at the University of Port Harcourt Teaching Hospital: A Retrospective Review

Malaria has continued to be an endemic disease of the tropics and subtropics. Malaria in the newborn is a global public health challenge with a high mortality rate in developing countries. A descriptive retrospective study over a 5 years period (2006-2011) conducted at the University of Port Harcourt Teaching Hospital. Information on Socio-demographic data, malaria parasite laboratory result and clinical information were retrieved from the medical microbiology departmental result registry. There was an overall 61% prevalence of malaria in neonates over the five years period with severe malaria occurring in 2.94% of them. Yearly Prevalence of malaria from 2006 to 2008 was 87.66%, 43.83%, and 70.74% respectively. There was about twelve percent decline in prevalence of malaria between 2009 and 2011 from 69.62% to 57.78% The study demonstrated a high prevalence of malaria in newborn in southern Nigeria, necessitating a need for high index of suspicion, early diagnosis, prompt and appropriate treatment to prevent neonatal mortality.


Introduction
Malaria is the most important disease caused by protozoa in the tropics. [1] It is caused by the parasite Plasmodium sp. In most cases the parasites are introduced into its host through a bite of an infected female anopheles mosquitos. Less commonly the disease is acquired congenitally through the placenta, through an infected blood transfusion, Perinatally due to mingling of blood during birth and through needle prick injuries. [1] Globally there are over 270 million new cases of malaria every year. [1] Over 80% of these are in Africa south of the Sahara. Annually there are 1.5-3million deaths from malaria and over 80% of these deaths are in Africa. [1] P. falciparum is responsible for 80%-90% of the malaria infections either alone or in combination with other species. [1] Repeated infections with the plasmodium results in development of natural immunity against the parasites. In the neonate, there is a passively acquired immunity from transplacental transfer of IgG from the mother to her feotus and this acquired immunity protects the newborn in the first few months of life. [1] Infection with Plasmodium sp is characterized by common symptoms such as headaches, fever, joint pains and vomiting. [2,3] In the newborn asexual malaria parasite detected in the cord blood or peripheral blood during the first week of life is termed congenital malaria and is due to transmission from the mother through placenta just before or during delivery [4,5] while acquired neonatal malaria, which can occur within the first 28 days of life is due to an infected mosquitos bite after birth. [4,5] It is difficult to differentiate between congenital and acquired malaria especially in malaria endemic areas like Nigeria [6]. Several studies in Africa have demonstrated that 7-10% of the newborns may have malaria parasites in their cord blood. [7] Neonatal malaria has been reported to be prevalent in malaria endemic areas such as Nigeria, despite the protective effects of maternal antibodies transferred to the neonate and the protection of the fetal haemoglobin in inhibiting Plasmodium sp development in the newborn [8][9][10]. Incidence of Neonatal malaria has been reported to range from 6 -20% across Africa [10][11][12][13] and from 1.1% to 5.1% across Nigeria [10,13] Malaria is a serious health challenge, with serious socioeconomic consequences especially in Nigeria which contributes to about one-quarter of the cases in the malaria endemic countries [10]. A retrospective study of malaria in the newborn as documented in medical microbiology registry of the department of medical microbiology and parasitology of the University of Port Harcourt Teaching Hospital from January 2006 to December 2011 was carried out.

Study Area
This study was carried out at the University of Port Harcourt Teaching Hospital (UPTH), Rivers state Nigeria. It is a tertiary health care institution that also attends to referral cases in the Niger-Delta region of Nigeria.

Study Population
All patients suspected of malaria in the neonatal group were included in the study. While patients above 1 month and patients with incomplete data were excluded from the study.

Data Collection
Data of the patients suspected of malaria and recommended for laboratory tests were retrieved from the laboratory records of the department of medical microbiology. Demographic data, results of laboratory tests were collected and analyzed with the statistical package for social sciences (SPSS) v20 (IBM, USA).

Data Analysis
The Chi-square test was used to compare proportion of malaria among the patients according to sex. All tests were carried out at a 95% confidence interval at a significant pvalue of ≤ 0.05 with the Epi Info v7 software (CDC, USA).

Discussions
The prevalence of malaria among neonates in this study is 61% and it is comparable to the prevalence rates between 61.1% and 71.4% as reported in previous studies in southern Nigeria [14][15][16] similar prevalence rates have been reported in endemic areas, with a high prevalence of malaria in the first three months of life. The occurrence of malaria in neonates have been attributed to congenital malaria as reported by Sotimehin [17]. The presence of parasites in the cord blood of 7-10% of newborns have been reported across Africa, sometimes without a symptomatic evidence of an active maternal infection, suggesting trans placental transfer of parasites to the fetus during pregnancy [18]. These high prevalence rates may result in childhood anemia and some other severe complications such as cerebral malaria and may also be potentially fatal to the infant [19,20] About 2.94% of the patients had severe malaria (≥3+ parasitemia), an indication of prevalence of congenital malaria as documented in similar studies across Africa [20][21][22]. Malaria in pregnancy has been reported to have a significant association with the occurrence of congenital and neonatal malaria, especially when the pregnant mothers do not receive adequate care and treatment of malaria during the depressed immunity state which is characteristic of pregnancy [21].
Among the patients with severe malaria, the most associated conditions were septicemia and severe anaemia. This is similar to the reports of other studies, indicating that these symptoms could lead to impaired immune responses to other infections especially in neonates with immature immune systems [18][19][20].
The occurrence of malaria ranged from 56% to 86% between March and July, while there was a decline in occurrence from 70% to 18% between August and December. This is in agreement with the findings of related studies, showing that occurrence of malaria is significantly higher during the period of heavy rainfall in endemic countries of Sub-Saharan Africa [9,16,22].
There was a decline in malaria prevalence from 70.74% to 57.78% between 2008 and 2011. This could be due to an improvement in the prevention and management of congenital malaria among pregnant women, based on the improved administration of the intermittent preventive treatment observed from the year 2005 in previous reports [23,24]. The decline in prevalence of malaria also coincides with the decline in child mortality recorded in the country.

Conclusions
The study is a confirmation of malaria in the newborn in South-South Nigeria, and calls for a high index of suspicion and an early screening of neonates for accurate diagnosis and prompt intervention that will prevent potential mortalities. Although malaria occurrence declined steadily from 70.7% to 57.7% between 2008 and 2011. There is a need to intensify efforts of preventing malaria in new born which will also contribute to the decline of child mortality a few weeks after birth.