Research Article - Asian Journal of Biomedical and Pharmaceutical Sciences (2019) Volume 9, Issue 68
Asymptomatic Plasmodium falciparum malaria infection in University undergraduate studentsUkibe Nkiruka Rose1*, Ukibe Solomon Nwabueze2, Onwubuya Ikechukwu Emmanuel3, Ofia Anya Kalu3
- *Corresponding Author:
- UkibeNkiruka Rose
Department of Medical Laboratory Science Nnamdi Azikiwe University Anambra State, Nigeria
E-mail: [email protected]
Accepted on July 04, 2019
Background: Malaria infection still remains a notable health problem in resource-limited countries due to difficulties in the implementation of control measures. This was a prospective study designed to assess the prevalence of asymptomatic P. falciparum malaria infection in premedical undergraduate students at Nnamdi Azikiwe University Nnewi, Nigeria. Methods: A total of 180 consenting apparently healthy subjects (male=90), female=90) aged 18-30 years were randomly recruited for this study. One millimeters of blood sample was collected from each of these participants and dispensed into EDTA bottle for P.falciparum malaria parasite screening using thick and thin film Giemsa staining technique and HRP2Pf rapid antigen diagnostic test kit (Access Bio Inc., USA). Results: Ninety nine (99) of these participants tested positive for asymptomatic P. falciparum malaria giving a prevalent rate of 55% while 81 subjects were uninfected and served as control The prevalence was higher in males (54.5%), underweight (46.5%) (P<0.0001) and among students aged 18-21 years (48.5%) followed by overweight (30.3%) students (P=0.039). Only (33.9%) of all the students used insecticide treated net (ITNs) (P=0.008). Conclusions: The present study showed high prevalence rate of asymptomatic P. falciparum malaria infection among university students who continuously served as reservoir for transmission to the uninfected ones which might progress to disease severity if left untreated.
Asymptomatic malaria, Plasmodium falciparum, Body mass index, undergraduate students
Increased burden of Plasmodium falciparum malaria infection and the overwhelming economic impact has become devastating to human health in endemic regions, Nigeria inclusive. Several researchers have shown that incidence of asymptomatic malaria is high in endemic areas [1-5]. These asymptomatic individuals can thrive for days or months without falling ill for malaria, thereby posing potential reservoirs for plasmodium transmission to the uninfected ones . This has been attributed to development of clinical immunity to plasmodium which enables the individual to reduce the parasite load and inflammation thus becoming symptomless. Special interventions that will target drugs to the asymptomatic parasite reservoirs have been strongly advocated in area of high transmission irrespective of their infection or symptom status. These include: routine screening of the population, routine administration of preventive malaria drugs and routine treatment of those infected with malaria parasite [7,8]. Use of insecticide treated bed nets (ITNs) is also recommended to reduce the constant exposures to mosquito bites . This may go a long way in complete reduction and eradication of malaria transmission to curb down the increasing burden and most of the mortality and morbidity seen in endemic regions. The present study therefore, seeks to investigate the prevalence rate of asymptomatic P. falciparum malaria infection among premedical undergraduate students at Nnamdi Azikiwe University, Nnewi Campus, Nigeria.
This was a prospective study designed to assess the prevalence of asymptomatic P. falciparum malaria in premedical undergraduate students of Nnamdi Azikiwe University, Nnewi Campus, Nigeria. A total of 180 participants (90 males and 90 female students) within the age range 18-30 years were recruited conveniently and subjected to malaria parasite (MP) screening. 99 of these subjects presented with asymptomatic P. falciparum malaria parasitaemia while the remaining 81 served as control. Questionnaires were administered to obtain the biodata of the entire subjects.
Inclusion and exclusion criteria
This comprised of apparently healthy male and female subjects aged between 18-30 years, who were asymptomatic to P. falciparum malaria infection and were not on any anti-malaria drugs prior to the time of sample collection. Subjects who were negative to P. falciparum after screening were used as control subjects. Pregnant women and lactating mothers were excluded. Subjects on antimalarial drugs and those with other debilitating diseases such as diabetes, typhoid and HIV infections, sickle cell anaemia were excluded from the study. Subjects outside the age range of 18-35 years were also excluded.
Two milliliter (1) of whole blood was collected by standard venipuncture technique and dispensed into EDTA bottle for P. falciparum malaria parasite screening using thick and thin film Giemsa staining technique and HRP2Pf rapid antigen diagnostic test kit (Access Bio Inc., USA).
The GraphPad Prism version 7.04 Statistical package was employed in the analysis of the result and the data obtained for different parameters were analyzed using percentage frequency and test of statistical significant differences using Chi-square (X2). Level of significance was set at P<0.05.
Out of 180 students that participated in the present study, 99 (55%) were asymptomatic for P. falciparum malaria parasitaemia. 75(41.7%) out of 180 participants were between the age range of 18-21 years and 48(48.5%) were asymptomatic for P. falciparum, 73(40.6%) were between the age range of 22-25 years and 39(39.4%) were asymptomatic for P. falciparum malaria. Those between age the range of 26-30 years were 32(17.7%) and 12 (12.1%) were positive for P. falciparum malaria.
Based on BMI, 54 (30.0%) were ≤ 18.5 kg/m2 (underweight) with 46(46.5%) asymptomatic malaria parasite infection. 30 (16.7%) of the participants were between 18.5-24.5 kg/gm2 (normal) and 13(13.1%) tested positive compared with 17(21%) of control counterpart. 72 (40.0%) were between 25.0-29.9 kg/m2 (overweight) and 30(30.3%) tested positive while 42(51.9%) were negative. Among the remaining 24 (13.3%) participants with BMI of ≥30 kg/m2 (Obese), 10 (10.1%) were positive for P. falciparum malaria parasitaemia.
In the present study, 90 (50%) of the participants were males and 54 (54.5%) tested positive to malaria, while 90(50%) were female and 45(45.5%) were positive to P. falciparum malaria parasitaemia.
Furthermore, 61(33.9%) of the overall participants uses insecticide treated bed nets (ITNs) while 119(66.1%) does not. Among the males, only 25(27.8%) out of 90 male participants uses ITN, while 65(72.2%) does not. 36(40.0%) out of 90 female participants uses ITN while 54(60%) does not. 8(8.08%) of asymptomatic malaria infected male participants uses ITN compared with 17(21%) of control participants. Also, 16(16.2%) of female participants uses ITN compared with their 16(19.8%) control counterpart (Table 1).
|Age range (years)||Frequency(N)(%)180(100)||Asym mp pos n(%) 99(55)||control mp neg n (%) 81(45)||p-value|
Table 1. Age range distribution of asymptomatic malaria infection.
Χ2=6.487, df=2. Level of significance was set at P<0.05. Key: Asym mp pos=Asymptomatic malaria parasite positive, mp neg=malaria parasite negative.
Level of significance was set at P<0.05. Key: Asym mp pos=Asymptomatic malaria parasite positive, mp neg=malaria parasite negative (Table 2).
|Gender||Frequency(N)(%) 180(100)||Asym mp pos n (%) 99(55)||Control mp neg n (%) 81(45)||p-value|
Table 2. Gender distribution of prevalence of asymptomatic malaria infection.
Χ=32.63, df=6. Level of significance was set at P<0.05. Key: BMI=Body mass index, Asym mp pos=Asymptomatic malaria parasite positive, mp neg=malaria parasite negative (Table 3).
|BMI (Kg/m2)||Frequency(N)(%) 180 (100)||Asym mp pos n (%) 99(55)||Control mp neg n (%) 81(45)||p-value|
Table 3. Prevalence of Asymptomatic malaria infection in association body mass index (Kg/m2).
Χ=11.96, df=3. Level of significance was set at P<0.05. Key: ITNs=insecticide treated bed nets, Asym mp pos=Asymptomatic malaria parasite positive, mp neg=malaria parasite negative (Table 4).
|ITNs Use||Frequency (N)(%)||Asym mp pos n (%)||Control mp neg n (%)||p-value|
|Non ITNs Use|
Table 4. Prevalence asymptomatic malaria infection according to ITNs use.
The present study was designed to assess the prevalence of asymptomatic P. falciparum malaria parasitaemia in premedical undergraduate students using some indicators: In the present study, it was observed that 55% of the study population had asymptomatic malaria parasitaemia. This has been attributed to development of clinical immunity which allows the individuals to control infection and become symptomless. High prevalence of asymptomatic P. falciparum malaria infection has been reported in endemic areas including Africa and other countries [4,10-12]. Significantly higher prevalence of asymptomatic malaria parasitaemia was observed among the age range 18-21 years followed by age range 22-25 years and least among age range 26-30 years. This suggests that plasmodium malaria parasite density decreases with increasing age meaning that the older ones develop immunity more than the younger individuals. It is also an indication that age is a risk factor in asymptomatic malaria infection. The present study is compatible with previous reports [11-14]. The observed increase in the prevalence of asymptomatic plasmodium malaria parasite infection in males when compared with females shows the effect of P. falciparum infection on gender. Previous findings have reported high prevalence of asymptomatic malaria in male than in females [11,15-17]. Further study by Andrade and Barrel-Netto,  also noted that gender is among the determinant factors of clinical outcomes in malaria infection.
Furthermore, prevalence of asymptomatic malaria parasitaemia was significantly higher in underweight participants followed by overweight and least in obese participants. This suggests a reduced clearance rate of the parasite load hence development of more clinical immunity than in the overweight and obese individuals. Excess body weight has been associated with reduced immune function including malaria infection  and time of residence in the endemic area and number of previous malaria episodes . After many years of repeated infections, the host develops clinical immunity against Plasmodium. In these cases, the onset of symptoms is prevented by limiting parasite burden and controlling inflammation. This might be attributed to the duration of stay of these students in the study environment.
In conclusion, the present study observed high prevalence of asymptomatic P. falciparum malaria parasitaemia among premedical undergraduate students. Drastic measures should be instituted for control of malaria in our University environment to ameliorate the risk, severity and fatal progression of asymptomatic to complicated malaria. Incentives on routine preventive therapy and free ITN should be introduced in tertiary institutions in endemic areas to curb the future menace of progression from asymptomatic infection to disease severity such as cerebral malaria and other neurological diseases in the study environment.
Ethics approval and consent to participate
The ethical approval for this research was obtained from ethics committee of Nnamdi Azikiwe University Teaching Hospital, Nnewi, Anambra State, Nigeria in accordance with the Helsinki declaration by the World Medical Association (WMA) on the ethics principles for medical research involving human subjects . Informed consent was obtained from the subjects prior to sample collection.
"NRU conceptualized the study design; NRU, SNU, EIO and AOK analyzed and interpreted the student’s data. NRU wrote the original manuscript. All authors read and approved the final manuscript.
- Cucunuba ZM, Guerra AP, Rahirant SJ, et al. Asymptomatic Plasmodium spp infection in Tierralta, Colombia. MemInst Oswaldo Cruz 2008; 103: 668-73.
- Baliraine FN, Afrane YA, Amenya DA , et al. High prevalence of asymptomatic Plasmodium falciparum infections in a highland area of western Kenya: a cohort study. J Infect Dis 2009; 200: 66-74.
- Marangi M, Di Tullio R, Mens PF, et al. Prevalence of Plasmodium spp in malaria asymptomatic African migrants assessed by nucleic acid sequence based amplification. Malar J 2009; 8: 12.
- Steenkeste N, Rogers WO, Okell L, et al. Sub-microscopic malaria cases and mixed malaria infection in a remote area of high malaria endemicity in Rattanakiri province, Cambodia: implication for malaria elimination. Malar J 2010; 9: 108.
- Adepeju IS. Prevalence of Malaria Parasite among Asymptomatic and Symptomatic Students of Federal University of Technology, Akure, Ondo State. Br J Res. 2017; 4: 5.
- Alves FP, Gil LH, Marrelli MT, et al. Asymptomatic carriers of Plasmodium spp as infection source for malaria vector mosquitoes in the Brazilian Amazon. J Med Entomol 2005; 42: 777-9.
- Macauley C. Aggressive active case detection: a malaria control strategy based on the Brazilian model. Soc Sci Med 2005; 60: 563–73.
- Kern SE, Tiono AB, Makanga M et al. Community screening and treatment of asymptomatic carriers of Plasmodium falciparum with arthmether-lumefantrine to reduce malaria disease burden: a modelling and simulation analysis. Malar J 2011; 10:210.
- Ukibe SN, Ikeako LC, Mbanugo JI, et al. Knowledge, Attitudes and Practices of Pregnant Women concerning the Use of Insecticide Treated bed nets (ITNs) in Anambra State, South –East Nigeria. J Adv Med Sci UK 2014; 3:15-22.
- Azeez OM, Raji Y. Family experience of ill health characteristics during rainy seasons. Sci Focus 2007; 12: 130-136.
- Taylor-Robinson AW. Increased production of acute-phase proteins corresponds to the peak parasitaemia of primary malaria infection. Parasitol Int 2000; 48: 297–301.
- Ibekwe AC, Okonko IO, Onunkwo AI et al. Comparative Prevalence Level of Plasmodium in freshmen (First Year Students) of NnamdiAzikiwe University in Awka, South-Eastern, Nigeria. Malaysian J Microbiol 2009; 5: 51-4.
- Baird JK, Jones TR, Danudirgo EW et al. Age-dependent acquired protection against Plasmodium falciparum in people having two years exposure to hyperendemic malaria. Am J Trop Med Hyg 1991; 45: 65-76.
- Munyekenye OG, Githeko AK, Zhou G, et al. Plasmodium falciparum spatial analysis, western Kenya highlands. Emerging Infect Dis 2005; 11: 1571-7.
- Eke RA, Chigbu LN, Nwachukwu W. High Prevalence of Asymptomatic Plasmodium Infection in a suburb of Aba Town, Nigeria. Ann Afr Med 2006; 5: 42-6.
- Epidi TT, Nwani CD, Ugorji NP. Prevalence of Malaria in Blood Donors in Abakaliki Metropolis, Nigeria. Sci Resear and Essay 2008; 3: 162-164.
- Ilozumba PC, Uzozie CR. Prevalence of malaria parasitaemia and its association with ABO Blood Group in Odoakpu Area of Onitsha South Local Government Area, Anambra State Nigeria. Nigerian Annals of Natural Sciences 2009; 8: 1-8.
- Andrade BB, Barral Netto M. Biomarkers for susceptibility to infection and disease severity in human malaria.MemInst Oswaldo Cruz, Rio de Janeiro, 2011; 106: 70-8.
- Tanaka SI, Isoda F, Ishihara Y et al. lymphopaenia in relation to body mass index and TNF in human obesity: adequate weight reduction can be corrective. Clin Endocrinol. 2001; 54: 347-54.
- Rogier C, Trape JF. Study of premunition development in holo- and meso-endemic malaria areas in Dielmo and Ndiop (Senegal): preliminary results, 1990-1994. Med Trop (Mars). 1995; 55 (Suppl. 4): 71-6.
- Bejon P, Warimwe G, Mackintosh CL, et al. Analysis of immunity to febrile malaria in children that distinguishes immunity from lack of exposure. Infect Immun 2009; 77: 1917-23.
- Levine RJ. Some Recent Developments in the International Guidelines on the Ethics of Research Involving Human Subjects. Ann New York Aca Sci 2000; 918: 170–8.