Introduction

Opportunistic infections (OIs) remain a major concern in people living with Human Immunodeficiency Virus (PLWH) [1]. OIs in these individuals can be caused by viruses, bacteria, fungi, and protozoa [2]. Human cytomegalovirus (HCMV) is one of the highly prevalent human herpesviruses that cause OIs in PLWH. Although it has a global endemicity, it is more widespread in developing countries than in developed countries [2, 3].

In most cases, primary HCMV infection is asymptomatic in immunocompetent individuals, and the virus usually establishes a latent infection upon resolution of the acute phase [4]. However, in PLWH, this latent infection becomes reactivated and causes a systemic disease, which in turn causes high morbidity and mortality [4–6]. The effect is worse among HIV patients who are not on ART than those who are on ART [7]. In PLWH, CMV causes various life-threatening infections like retinitis, pneumonia, encephalitis, enteritis, etc. [1, 6]. These infections last a lifetime and can antagonize the immune system endlessly [8]. During infection with HCMV, specific antibodies against the virus are produced. The first type of antibody to develop is HCMV specific IgM, while IgG antibody is produced later. The CMV IgM produced then remains detectable for a longer period even after the resolution of a primary infection. Besides primary infection, IgM/IgG antibodies can also be detected during secondary infection either as re-activation or as re-infection [2].

Unless the virus is diagnosed early and appropriate treatment is given, HCMV viremia hastens the HIV disease progression by accelerating the immune system aging and eventually leads to death [9–11]. The two commonly used laboratory methods for the detection of HCMV among PLWH are PCR (that detects the virus replication) and serum immunological methods like ELISA (that detects antibodies produced against the virus) [1]. However, due to delayed CMV antibody production in PLWH that can lead to a false-negative result, PCR is the preferred diagnostic method for the detection of HCMV infection [1]. Since a late diagnosis of CMV infection is reported to cause dismal outcomes among PLWH, early diagnosis of the virus in these individuals is very critical for the management and monitoring of the infection [12].

Despite its cruciality, diagnostic testing for HCMV is not routinely done globally in PLWH [13]. In developing countries, the diagnosis and treatment of HCMV infection remain a challenge that has received little attention although the ART is scaled-up [14, 15]. Similarly, no study was done concerning HCMV infection among treatment-naive HIV infected people from Ethiopia as far as our knowledge is concerned. Therefore, this study was aimed at determining the prevalence of HCMV among treatment-naive HIV infected study subjects in Addis Ababa.

Methods

Results

Sociodemographic and clinical characteristics of study participants

Of the 97 consented HIV-1 infected study participants, about 59% (n = 57) of them were females, comprising a 1:1.43 male to female ratio (Table 1). Among the HCMV seropositive subjects, 58.3% (n = 7) of them were female while 41.7% (n = 4) were male. The ages of the study participants ranged from 19 to 57 years old. The average age of study participants was 32 years. Looking at the HIV-1 viral load level, more than half (50.8%) of the patients studied had a viral load of ≤ 100, 000 copies/ml (Table 1). Concerning HCMV IgM seropositive subjects, the majority (66%) of them had HIV-1 viral load > 100, 000 copies/ml (Table 1). Similarly, 50% of the HCMV DNA positive subjects had HIV-1 viral load > 100, 000 copies/ml (Table 1).

Table 1

Sociodemographic and clinical characteristics of study participants.

Characteristics		Frequency (N)	Percentage (%)	Individuals with HCMV ELISA positive (N)		Individuals with HCMV DNA (N)
				(N)	(%)	(N)	(%)
Sex	Male	40	41.2	5	41.7	1	25
	Female	57	58.8	7	58.3	3	75
Age Category	18–28	38	39.2	5	41.7	2	50
	29–38	38	39.2	4	33.3	1	25
	39–48	15	15.5	1	8.3	0	0
	>49	6	6.2	2	16.7	1	25
Current HIV-1 Viral load (Copies/ml)	<2000	11	11.3	1	8.3	0	0
	2000–10000	9	9.3	0	0	0	0
	10001–100000	35	36.1	3	25	2	50
	>100000	42	43.3	8	66.7	2	50
Occupation	Unemployed	43	44.3	5	41.7	0	0
	Employed	54	55.7	7	58.3	4	100
Marital status	Married	43	44.3	3	25	1	25
	Single	28	28.9	4	33.3	2	50
	Stable relationship but not married	1	1	1	8.3	0	0
	Divorced	15	15.5	3	25	0	0
	Widowed/widower	10	10.3	1	8.3	1	25
Educational status	No schooling	17	17.5	2	16.7	0	0
	Primary	26	26.8	1	8.3	2	50
	Secondary	37	38.1	4	33.3	1	25
	College (diploma)	7	7.2	2	16.7	0	0
	University degree	10	10.3	3	25	1	25

HCMV serology

Of 97 study participants, 12/97 (12.4%) of them showed HCMV IgM antibody positive results not confirmed by PCR test (Table 2). Although not statistically significant, the seroprevalence of the HCMV IgM antibody was slightly higher in the female participants (58.3%) than in males (41.7%). In addition, 66% of the HCMV IgM seropositive subjects had HIV-1 viral load > 100,000 copies/ml but the association was not statistically significant.

Table 2

Comparison of conventional PCR and ELISA for HCMV detection in plasma samples of the ART-naive HIV-1 infected individuals.

		Conventional PCR
		Positive	Negative	Total
IgM ELISA	Positive	0	12	12
	Negative	4	81	85
	Total	4	93	97

Discussion

The early detection and intervention of opportunistic viruses such as HCMV among PLWH are very crucial for delaying HIV disease progression [9]. Albeit the high HIV prevalence, there are only limited studies done concerning HCMV infection in Africa. Similarly, there is no documented report regarding HCMV co-infection among treatment-naive HIV infected individuals from Ethiopia. Here we reported the HCMV IgM seroprevalence and HCMV viremia among treatment-naive HIV-infected individuals from Ethiopia using both ELISA and conventional. Since the demographics of the cohorts in this study is similar to the demographics of treatment-naive PLWH in Ethiopia, we believe that this study is reflective of the general population.

In line with studies from Nigeria (11.7) [2] and the USA (17%) [18], the HCMV IgM seroprevalence in the current study was 12.4%. However, the magnitude of the HCMV in the current study is higher than those that are reported from other countries; Serbia (7.1%) [19], Sudan (6.1%) [20]. This could be due to the difference in the study populations. Besides, the HCMV IgM seropositivity in the current study was not confirmed by PCR similar to other studies [19–21]. The inability to detect HCMV DNA in patients who were IgM positive might be due to the persistence of IgM antibodies for an extended period after primary infection [22, 23]. After the resolution of primary infection, HCMV specific IgM can be detectable for an average of 6 to 9 months [2].

Concerning the HCMV PCR in the current study, 4.1% (4/97) of the study subjects were HCMV PCR positive. This is consistent with the studies from South Africa, which were reported to be 5.2% [24], and India (7%) [25]. However, the current finding is lower relative to the findings from Tanzania (22.6%) [14], Kenya (17%) [26], and Cambodia 55.2% [27]. With respect to sex distribution, 75% of participants with confirmed HCMV DNA were females and this is in line with a previous study from Sudan [28].

In this study, the HCMV PCR positive samples were negative for ELISA IgM antibodies similar to other studies from Sudan [20, 29, 30]. The absence of HCMV IgM antibody in those PCR positive individuals could be due to the time lag between primary infection and IgM antibody production since IgM antibodies may remain undetectable because of delayed seroconversion [22, 23]. Besides, those PCR positive subjects might have reactivated HCMV infection, which usually does not induce a strong IgM response leading to a negative ELISA IgM result.

The presence of HCMV DNA (HCMV viremia), which is a better indicator of active HCMV infection [6], has been described as a well-known risk factor for mortality of treatment-naive HIV-infected individuals [24, 31]. Besides, the detection of HCMV DNA in patients with HIV has been serving as an AIDS-defining marker in the past. A study from Norway described that HCMV disease has served as the AIDS-defining diagnosis in 13 patients (6.1%) who died from AIDS [31]. Based on this, HCMV DNA detection among PLWH in the current study could be an early predictor of disease progression. A study from California also supports the hypothesis that HIV infected patients with DNAemia/positive plasma HCMV DNA were shown to be correlated with a 2.5-fold increased risk of death over 650 days [32]. Similarly, a study done in South Africa indicated that subclinical CMV viremia was an independent risk factor for mortality among adult males living with HIV in South Africa [33]. These findings suggest the need for early diagnosis and subsequent treatment of HCMV infection.

The prophylactic HCMV therapy has been shown to reduce the risk of CMV disease if initiated early upon HCMV infection diagnosis [34]. So far, there are four antiviral drugs licensed for the treatment of HCMV infections: ganciclovir, valganciclovir, foscarnet, cidofovir, and letermovir [35]. Due to the cost barrier, only ganciclovir was in use in developing countries in the past. However, valganciclovir is now started to be introduced in low and middle-income countries as it is available at a reduced price within the WHO essential medicines list [36, 37].

In this study, we have reported the HCMV seroprevalence and HCMV viremia among treatment-naive patients in Ethiopia for the first time. Apart from this strength, however, due to reagent shortages, we did not include a CD4 count that made a description of HCMV among PLWH in terms of immunosuppression difficult.

Conclusions

The prevalence of HCMV infection according to the PCR test was 4.1%. As it was reported in the literature about the association of HCMV viremia and the development of CMV disease, a routine laboratory diagnosis is highly critical in preventing this disease ahead of time. Besides, the use of anti-CMV therapy parallel to ART for CMV viremic individuals is also recommended as this can reduce the burden of CMV complications and consecutively prolonging the life of PLWH. Moreover, we recommend further studies with a large sample size to be done at a national level to see the overall picture of HCMV-HIV co-infection at a national level, which in turn helps to develop national disease prevention and treatment plan and/or guideline.