Parasitic infections (especially malaria and intestinal parasites) are major public health concern in PLWH in developing countries, particularly Sub-Saharan Africa which has been reported to have the highest burden of HIV [2]. This study was a hospital- and community-based cross-sectional study carried out to determine the prevalence of malaria and intestinal parasites among PLWH and HIV negative individuals in Buea, in South West Region of Cameroon.
In the present study, the overall prevalence of malaria parasite was 16.6%, irrespective of the HIV status of the participants. This result is lower than the recently reported national prevalence (24.4%) [30]. This decrease could be attributed to the restless efforts of the Cameroon government over the years to implement malaria control strategies so as to curb down malaria morbidity and mortality on the entire territory; knowing that Cameroon comes fourth on the list of countries that account for the burden of malaria in the WHO African Region [5].
The prevalence of malaria parasite among PLWH was 16.4%, which is high compared to the prevalence reported in PLWH in other areas of the South West Region of Cameroon. This included the 7.8% reported in Limbe [10] and 2.3% in Buea [31] It was also observed in this study that despite the efforts made to scale up insecticide-treated nets (ITNs) distribution so that universal coverage can be attained, coverage remains low and this could have contributed to this rise in malaria prevalence among PLWH.
The prevalence of malaria parasite was higher in HIV negative participants (21.3%) than in their HIV positive counterparts. This finding is in line with studies carried out in Cameroon [10] and Ethiopia [32] which also reported a higher malaria parasite prevalence in HIV negative participants at the OPD of the hospital when compared with their HIV positive counterparts. Although HIV positive patients are considered as a high-risk group for malaria, malaria is not the most frequent diagnosis in these patients. Majority of the HIV positive patients were under a combination therapy of ART and cotrimoxazole which probably protected them against infections. Cotrimoxazole has been reported in several studies to have some protective effect against parasitic infections, both in clinical trials [33, 34, 35] and in the hospital [22].
In this study, while MP prevalence was higher among HIV patients who did not attain viral suppression (viral load ≥ 50 copies/ml of blood), the majority of the HIV positive patients attained viral suppression due to their adherence to ART over the years. This is in line with recent findings in western Kenya [36] and further confirms the benefits of adherence to ART.
It is worth noting that HIV negative participants from the Buea communities had the least malaria parasite prevalence (14.8%) when compared with their counterparts. These malaria asymptomatic carriers are those who greatly fuel the transmission of malaria parasite in the community. This low prevalence shows that strategies implemented by the Cameroon government over the years are effective as this prevalence is lower than the reported national prevalence of malaria in 2018 [5].
Fever is one of the most common clinical sign and characteristic feature of both parasitic and microbial infections. In this study, febrile status of most of the participants irrespective of their study group was attributed to the presence of malaria parasite. This is in line with other studies carried out in Cameroon [10] and in Gabon [37] Also feverish PLWH had the highest prevalence of MP/IPs co-infection asserting the fact that fever remains an important feature in the clinical diagnosis of infections.
The prevalence of IPs in Cameroon varied from 27.8% in 2012 [38], to 14.6% in 2013 [39] and 13.0% in this present study. Considering the HIV status, PLWH had the highest prevalence of IPs (23.7%) when compared with their HIV negative counterparts. This prevalence among PLWH is lower than the 59.52% [39] and 57.48% [40] reported among HIV patients in the Centre and West Regions of Cameroon respectively. This observed decrease in the prevalence of IPs among HIV patients may be accredited to attainment of viral suppression by a majority as well as their better awareness of IPs and their causes. It may also be due to the improvement in care provided to PLWH by the government of Cameroon by ensuring a constant supply and provision of ART free of charge.
In line with other studies in Cameroon [15], Ethiopia [41] and in China [42], the prevalence of protozoa was higher than that of helminths. Both the HIV positive and HIV negatives were infected with Cryptosporidium spp; but PLWH had the highest prevalence of Cryptosporidium spp (16.8%). The prevalence of Cryptosporidium spp in this study is lower unlike the 44% reported earlier in Cameroon [15] and the 79.0%, in South Africa [43]. Cryptosporidium spp is recognized as an opportunistic parasite in HIV/AIDS patients because it tends to be present when the CD4 + T cell counts are below 200 cells/µL. Hence, this decreased prevalence among HIV patients could be attributed to the success of intervention efforts over the years in reducing the significance of opportunistic intestinal parasites in this at risk group. Hookworm was the most prevalent helminth among HIV patients with a prevalence of 2.6%. A prevalence of 2.53% and 2.7% have also been reported in studies carried out in Yaounde, [40] and in Buea [44] Cameroon.
This study revealed 3.7% of PLWH were co-infected with MP and IPs. Limited information is available on co-infection among PLWH in Cameroon; but when compared with other studies carried out among children [18, 45, 46], the prevalence is low. The mean age (35.5 ± 16.5 years) of PLWH as well as the undetectable viral load observed in the majority of these patients could account for this low prevalence. The lower the viral load, the faster the patient’s immune system will recover, increasing the chances of fighting any infection easily. In addition, majority of this patients have been on ART regularly for more than a year which probably could have contributed in boosting their immune system against these parasites.
The overall prevalence of anaemia of 56.6% irrespective of their HIV status is higher than the 52.1% reported in previous study in the Mount Cameroon area [10].This increase may be attributed to the rise in malaria parasite prevalence observed in the study when compared with previous studies in the area. Several authors have reported malaria parasite as a risk factor of anaemia [47, 48] due to the pathogenesis of the infection that involves the destruction of both infected and non-infected red blood cells.
PLWH had a higher prevalence of anaemia (76.8%) when compared with their HIV negative counterparts. This prevalence is higher than the less than 56.0% reported in several studies carried out among PLWH [49, 9, 50, 51, 52, 53, 10]. The reason for the observed difference might be due to the heterogeinity of the study population as these previously reported anaemia prevalences were those of children or adults HIV patients, but this study included both children and adult participants. Malaria and HIV positivity, as well as fever were identified in this study as risk factors of anaemia and therefore contributed significantly to the high prevalence of anaemia. Mixed nutritional deficiencies (iron, folic acid, or vitamin B12), though not investigated in this study, could have contributed to this high prevalence of anaemia as reported by a study carried out by Volberding et al., [54]. A direct comparison of prevalence of anaemia in different studies is difficult as the study population, inclusion and exclusion criteria and anaemia definitions were different.
Parasites like the malaria parasites and intestinal parasites have long been recognized as major contributors to reduced haemoglobin levels in endemic countries like Cameroon, thereby causing anaemia. In addition, PLWH on ART (containing Zidovudine) have been reported to influence the haemoglobin level in previous studies [55, 56, 57, 9, 10]. In this study, patients infected with both HIV, malaria and IPs had a significantly lower mean haemoglobin value (10.6 ± 1.21 g/dL). This in line with previous studies which reported though among children, low haemoglobin values in patients with co-infections when compared with those with single infections [58; 59].
The higher prevalence of Leucopenia observed among PLWH (55.5%) when compared with HIV negative counterparts has been reported in studies carried out in Ethiopia [60], Nigeria [61] as well as in Cameroon [50]. This high prevalence could be associated with profound immunodeficiency as more than half of PLWH had CD4 T cell count < 500 cells/µL of blood. While observation from this study revealed no significant difference in the prevalence of thrombocytopenia between PLWH and HIV negative participants, a decrease has been reported in other studies after ART introduction [62, 63]. Microcytosis was present among PLWH but the prevalence was lower (43%) when compared with their HIV negative counterparts. As PLWH attend an HIV specialty unit, they often receive medical talks with respect to their immunity, nutritional status and general wellbeing as part of the case management. This could have contributed to the low prevalence of microcytosis in this group which is often due to iron deficiency.
Even though different types of HIV and MP species have been reported in Cameroon, limited knowledge exist on the occurrence of MP/IPS co-infection among PLWH. Findings of this study fills some of the gaps although it has its limitations. Notwithstanding, the fact that ART-naïve HIV infected patients were not included in the study, nutritional deficiency as a cause of anaemia was not investigate, as well as the cross sectional nature of the study that provides a picture at a point in time, the findings are valuable to policy makers in guiding the management of these conditions. Future longitudinal studies on the impact of iron supplementation and vitamin B12 levels among PLWH may be of great relevance.