higher for the women anaemic at every follow-up visit. The mean ferritin was lower (35.4 vs. 61.2 ng/mL, p = 0.0107) for the women anaemic at every visit as well. Discussion This study demonstrated a decline in haemoglobin levels following HIV-1 subtype C infection and a rise in the prevalence of anaemia from 25.0% prior to HIV-1 infection to 52.6% at 3 months post- infection, 61.1% at 6 months post-infection, and 51.4% at 12 months post-infection. The haemoglobin declined by 0.46 g/ dL at the time of acute infection, by 0.93 g/dL during the first 6 months following infection, and then by a mean of just 0.10 g/dL in the subsequent 6 months. The mean haemoglobin was lowest and the prevalence of anaemia was highest at 6 months post-infection. In the following 6 months, the haemoglobin level remained low and did not recover to pre-infection levels. This observation may reflect that perturbations of haematopoiesis or of the red cell life cycle are occurring early in the course of HIV infection and that these parameters begin to stabilize at 6 months post-infection. Unfortu- nately, reticulocyte counts were not obtained and so we can only infer the haematopoietic response from the available parameters. The anaemia of these participants trended towards microcytosis and hypochromia and this trend persisted throughout the first 12 months following HIV-1 infection. The trend towards microcytosis combined with the progressive decline in serum iron levels and the elevated red cell distribution width (RDW) point towards iron-deficiency as the most likely etiology of the anemia in this cohort. Although the slight elevations in serum ferritin in this cohort do not correspond with the typical profile of iron- deficiency, ferritin is an unreliable indicator of underlying iron- deficiency in the setting of acute infection. Anaemia seen this early following acute infection could be thought to reflect impaired haematopoiesis in the setting of early, uncontrolled viral replication and an excess of inflammatory cytokines[17], as shown by our results at the time closest to HIV infection. There was no significant correlation between haemo- globin level or rate of haemoglobin decline and viral load at 6 or 12 months post-infection. Previous reports have suggested that there is an increased risk of anaemia with more advanced HIV infection[5], however, here we demonstrate that anaemia occurs with increasing frequency during the early stages of HIV-1 infection. Whether this acute infection References 1. Kreuzer KA, Rockstroh JK (1997) Pathogenesis and pathophysiology of anemia in HIV infection. Ann Hematol 75: 179–87. 2. Savarino A, Pescarmona GP, Boelaert JR (1999) Iron metabolism and HIV infection: reciprocal interactions with potentially harmful consequences? Cell Biochem Funct 17: 279–287. 3. Lau B, Gange SJ, Phair JP, Riddler SA, Detels R, et al. (2005) Use of total lymphocyte count and hemoglobin concentration for monitoring progression of HIV infection. J Acquir Immune Defic Syndr 39(5): 620–625. 4. Moore R (1999) Human immunodeficiency virus infection, anemia, and survival. Clin Inf Dis 29: 44–49. 5. Semba RD, Shah N, Klein RS, Mayer KH, Schuman P, et al. (2002) Prevalence and cumulative incidence of and risk factors for anemia in a multicenter cohort study of human immunodeficiency virus-infected and -uninfected women. Clin Inf Dis 34: 260–66. 6. Lundgren JD, Mocroft A (2003) Anemia and survival in human immunodefi- ciency virus. Clin Inf Dis 37(Suppl 4): S297–303. 7. Mocroft A, Kirk O, Barton SE, Dietrich M, Proenca R, et al. (1999) Anaemia is an independent predictive marker for clinical prognosis in HIV-infected patients from across Europe. AIDS 13: 943–950. 8. Sullivan PS, Hanson DL, Chu SY, Jones JL, Ward JW (1998) Epidemiology of anemia in human immunodeficiency virus (HIV)-infected persons: results from the multistate adult and adolescent spectrum of HIV disease surveillance project. Blood 91(1): 301–308. 9. Zhou J, Kumarasamy N, TREAT Asia HIV Observational Database (2005) Predicting short-term disease progression among HIV-infected patients in Asia Anaemia in Acute HIV Infection associated anaemia will resolve during the typically latent period prior to clinical AIDS remains to be seen. Furthermore, whether the presence or severity of anaemia during acute HIV-1 infection will predict anaemia in chronic infection and/or more rapid disease progression also remains to be seen. Given the results of Deschamps and colleagues in Haiti that anaemia at seroconversion predicted a four-fold more rapid progression to AIDS[16] and the results of other studies that have found anaemia at any point in HIV infection to be an independent risk factor for decreased survival [18], anaemia is a potentially early indicator of more rapid clinical course and could factor into clinical algorithms regarding antiretroviral initiation, particularly in resource constrained settings. Additionally, in light of the propensity for certain antiretroviral medications such as Nevirapine and Zidovudine (AZT) to exacerbate underlying anaemia, a high prevalence of anaemia in patients awaiting therapy could factor into decisions regarding medication choice. It will be important to confirm these results in other cohorts and to continue to characterize the relationship between anaemia and clinical course of HIV-1 infection as this cohort progresses into established infection. Additionally, since this cohort was comprised entirely of women, it is unknown if these same patterns will hold true for men. Although since women are at greater baseline risk for anaemia than men, it is important to characterize the increased burden that HIV-infected women will face. Anaemia is a common problem among South African women and, according to our results, becomes more common with early HIV-1 infection. The increasing prevalence of anaemia in this population during early HIV-1 infection is concerning in light of the detrimental impact of low haemoglobin on energy and physical functioning [19]. Further prospective data is necessary to define the significance of these findings and to determine the impact of anaemia in acute infection on subsequent disease progression. The ongoing CAPRISA Acute Infection study will continue to follow the cohort described in this report to investigate whether anaemia during acute HIV-1 infection has any long-term consequences. 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