In total HIV positive patients167 (9.6%) of the studied patients were seropositive for T.pallidum. This finding was similar to a prevalence rate of 10.0% reported in a study done in Uganda by Mboowa et al (11). It was as well similar to finding from a an Ethiopian study where 30 (9.8%) out of 306 HIV positive patients were found to be positive for seropositive for T.pallidum(10). This study showed lower Seroprevalence as compared to study done in Ghana by Mamoojee where 45(14.8%) out of 284 HIV positive participants and higher than study done in Rwanda by Mutagoma 20 (4.8%) out 482 HIV positive participant.
People who reported being married to one person were significantly more frequently seropositive for T.pallidum (56.3% versus 53.5% in the TPHA negative).This finding was similar to study results in Uganda and Ethiopia, and was presumed to be because of concurrency of partners. Specifically, Kenyon et al reported that male partner concurrency in which men had an average of five concurrent partners was significantly associated with high prevalence of syphilis (46). People who were TPHA positive were significantly more likely to have only a primary education, perhaps suggesting that they may have lacked knowledge on preventive measures against sexually-transmitted infections. This finding was contrary to the study done in Ethiopia in which having a secondary education was associated with TPHA positivity. Employed persons were less likely to have seropositive T.pallidum for is perhaps due to a reduced network of partners. Only 10% of patients who were seropositive for T.pallidum reported previous history syphilis. Syphilis is not screened routinely among people living with HIV or thought to be unimportant problem. Similarly high rates of undiagnosed syphilis have been reported from the Ethiopia study. For those who had syphilis, only two-thirds (67.7%) received treatment. The majority received three intramuscular penicillin doses according to CDC recommendation, as also reported by Katz and colleagues (47).
Most patients who were seropositive for T.pallidum had CD4+ T cells above 350 cells/uL (56.3%) and viral load levels less than 50 copies/mL (77.8%). We did not find an association between CD4 counts or viral loads. This might be because most of the patients in our study were on ART and in a latent stage of syphilis. Our results contrast with the study in the US by Kate et al which showed syphilis reduces CD4+ T cells and increases viral load (7), particularly in those with secondary syphilis on ART and those with syphilis not on ART. This study also showed that the majority of participants who were seropositive for T.pallidum reported no prior history of genital lesion (97.1%), possibly due to the painless lesions of syphilis that might go unnoticed primary stages. A study in Spain similarly found that few patients who were seropositive forT.pallidum reported a past genital lesion (13).
Among the 141 participants who were serum TPHA positive and returned to the clinic for neurological assessment, 3 participants had cognitive impairment. One of those with cognitive impairment had also hearing loss. The second patient had hearing loss alone with no other symptoms. The third patient had fever, headache, and altered mental status. The patients were also assessed for any sign of meningeal irritation but no one was positive. In addition, eye examinations identified no patient with typical features of ophthalmic syphilis. Patients were also examined for gait, unilateral weakness, and sensory modalities and were all found to be normal. This was contrasting to the study done US by Katz et al which had found 12 patients with neurosyphilis 4,of whom had eye problems, 3 altered mental status and five had unilateral weakness(47). Of note, a major difference between the Tanzania and the US study is that not all US patients were on ART, whereas all but one of the Tanzanian study patients were on ART.
Among the 141 screened by examination, only 4 (2.8%) had neurological symptoms necessitating lumbar puncture to assess for neurosyphilis. This was in accordance with expert guidelines recommending lumbar punctures not in all seropositive for T.pallidum plus HIV-positive patients, but only in those with neurological manifestation (8,15,48). In our study among the 4 participants with syphilis who underwent lumbar puncture one was confirmed to have neurosyphilis. That person had no prior history of syphilis and was not on ART. TheCD4+ T cell count was 412 cells/uL. The patient was treated with daily intravenous ceftriaxone per the CDC guideline but died after 3 days in the ward after rapid neurologic deterioration. This patient might have suffered from the meningoencephalitis form of neurosyphilis which has fast progression with poor prognosis in HIV positive patients. This form of neurosyphilis was seen in one case study in an HIV-positive patient who presented with abnormal behavior (49). In HIV positive patients might have normal CD4+ T cells with altered function increasing the risk of syphilitic meningoencephalitis this was observed in a study Mark et al(50). Likewise in study done by Marra et al in US found 16 neurosyphilis patients with only CSF-VDRL among 50 patient with neurosyphilis (51). By contrast, in the study done in Spain by Alverez et al, all patients who had a diagnosis of neurosyphilis presented with mild headache, had no prior history of treatment, and improved after therapy (13). The three patients who were negative for neurosyphilis, all were on ART and reported no history of prior treatment for syphilis. This may have occurred because ART use reduces the chances of having neurosyphilis to be equal to that of HIV-unpositive people with syphilis (43).
In our study we found a prevalence of neurosyphilis of only 0.7% of all who were examined for neurologic features. This prevalence was surprisingly low given the findings of other studies that have suggested the prevalence could be as high as 25%. This low prevalence may be due either to ART use in most patients, or possibly having been previously treated with antibiotics, for a different indication, that have activity against Treponema pallidum. Our findings on neurosyphilis fit with a systemic review of neurosyphilis in Africa by Mark et al(52), which found only two patients with meningitis (3.3%).Another study done in Brazil by Jacquelline et al had showed to be 1% among HIV positive patient with neurologic features(53). In contrast, a study by Borden et al showed that 23.5% seropositive for T.pallidum patients who were not on ART had neurosyphilis. (13). Therefore, our study documents an important and encouraging finding that rates of neurosyphilis are lower in our setting than previously reported. This may be due to the expanding use of ART and also to the use of antibiotics, some of which may be excess but may serve inadvertently to treat seropositive for T.pallidum patients and prevent neurosyphilis.
Our study had some limitations It was difficult to know if patients were previously treated for syphilis with other agents which active for syphilis like ceftriaxone or doxycycline because of the lack of electronic data keeping. In our study we excluded patients without neurologic features for lumbar puncture hence we may have missed asymptomatic neurosyphilis. We were not able to determine whether a patient may have had seroreversion of syphilis as the reagent used was only qualitative and usually stays positive for life. Risk factor for neurosyphilis could not be determined due very small number. HIV-positive patients with neurosyphilis may die rapidly and this cross-sectional study would not have found those patients