Provision of HIV services by community health workers should be strengthened to achieve full programme potential: a cross-sectional analysis in rural South Africa.

OBJECTIVE: South Africa's community health workers (CHWs) provide a bridge between the primary healthcare (PHC) facility and its community. We conducted a cross-sectional analysis to determine the contribution of the community-based HIV programme (CBHP) to the overall HIV programme. METHODS: We collected service provision data from the daily activity register of CHWs attached to 12 PHC facilities in rural Mopani District, South Africa. Personal identifiers of individuals referred to the facility for HIV services were recorded and verified against facility routine patient registers to determine the effectiveness of referral. RESULTS: HIV services were provided on 18 927 occasions; 30% of the total activities performed by CHWs during the study period. CHWs assessed 12 159 individuals for HIV risk (13% coverage of the study population); only 290 (2%) were referred for HIV testing services. Referral was effective in 213 (73%) individuals; evidence of an HIV-positive status was found for 38 (18%) individuals. However, 30 (79%) of these individuals were referred by CHWs despite being on ART. Adherence support was provided during 5657 visits; only one individual was referred for complications. Finally, of the 864 individuals lost to the ART programme, CHWs managed to find 452 (52%) for referral back to the facility; only 241 (53%) of these were (re)initiated on ART. CONCLUSIONS: Provision of HIV services by CHWs should be strengthened to fully deliver on the programme's potential. Human resource investment, home-based HIV testing and improved tracing models constitute potential strategies to enhance CHWs impact on the HIV programme.

OBJECTIF: Les agents de santé communautaires (ASC) d'Afrique du Sud constituent un pont entre les établissements de soins de santé primaires et leur communauté. Nous avons effectué une analyse transversale pour déterminer la contribution du programme VIH basé sur la communauté (PVBC) au programme global de lutte contre le VIH. MÉTHODES: Nous avons collecté des données sur la prestation de services à partir du registre des activités quotidiennes des ASC rattachés à 12 établissements de soins de santé primaires dans le district rural de Mopani, en Afrique du Sud. Les identifiants individuels des personnes référées vers l'établissement pour des services VIH ont été enregistrés et vérifiés par rapport aux registres de routine des patients de l'établissement afin de déterminer l'efficacité de l'aiguillage. RÉSULTATS: Les services VIH ont été fournis dans 18.927 occasions; 30% du total des activités réalisées par les ASC au cours de la période d'étude. Les ASC ont évalué 12.159 personnes pour les risques du VIH (couverture de 13% de la population étudiée); seuls 290 (2%) ont été référés pour des services de dépistage du VIH. L'aiguillage a été efficace chez 213 personnes (73%). L'évidence de séropositivité a été trouvée chez 38 personnes (18%). Cependant, 30 (79%) de ces personnes ont été référées par des ASC alors qu'elles étaient sous ART. Un soutien à la compliance a été fourni au cours de 5.657 visites; un seul individu a été référé pour des complications. Enfin, sur 864 personnes perdues du programme ART, les ASC ont réussi à retrouver 452 (52%) pour les référer de nouveau à l'établissement; seuls 241 (53%) de celles-ci ont été (ré) initiées sous ART. CONCLUSIONS: La fourniture de services VIH par les ASC devrait être renforcée pour exploiter pleinement le potentiel du programme. Les investissements dans les ressources humaines, le dépistage du VIH à domicile et les modèles de traçage améliorés constituent des stratégies potentielles pour améliorer l'impact des ASC sur le programme VIH.

The impact of implementing a Xpert MTB/RIF algorithm on drug-sensitive pulmonary tuberculosis: a retrospective analysis.

Xpert MTB/RIF (Xpert) is the preferred first-line test for all persons with tuberculosis (TB) symptoms in South Africa in line with a diagnostic algorithm. This study evaluates pre- and post-implementation trends in diagnostic practices for drug-sensitive, pulmonary TB in adults in an operational setting, following the introduction of the Xpert-based algorithm. We retrospectively analysed data from the national TB database for Greater Tzaneen sub-district, Limpopo Province. Trends in a number of cases, diagnosis and outcome and characteristics associated with death are reported. A total of 8407 cases were treated from 2008 until 2015, with annual cases registered decreasing by 31·7% over that time period (from 1251 to 855 per year). After implementation of Xpert, 69·9% of cases were diagnosed by Xpert, 29·4% clinically, 0·6% by smear microscopy and 0·1% by culture. Cases with a recorded microbiological test increased from 76·2% to 96·4%. Cases started on treatment without confirmation, but with a negative microbiological test increased from 7·1% to 25·7%. Case fatality decreased from 15·0% to 9·8%, remaining consistently higher in empirically treated groups, regardless of HIV status. Implementation of the algorithm coincided with a reduced number of TB cases treated and improved coverage of microbiological testing; however, a substantial proportion of cases continued to start treatment empirically.

A 10-year cohort analysis of routine paediatric ART data in a rural South African setting.

South Africa's paediatric antiretroviral therapy (ART) programme is managed using a monitoring and evaluation tool known as TIER.Net. This electronic system has several advantages over paper-based systems, allowing profiling of the paediatric ART programme over time. We analysed anonymized TIER.Net data for HIV-infected children aged <15 years who had initiated ART in a rural district of South Africa between 2005 and 2014. We performed Kaplan-Meier survival analysis to assess outcomes over time. Records of 5461 children were available for analysis; 3593 (66%) children were retained in care. Losses from the programme were higher in children initiated on treatment in more recent years (P < 0·0001) and in children aged ≤1 year at treatment initiation (P < 0·0001). For children aged <3 years, abacavir was associated with a significantly higher rate of loss from the programme compared to stavudine (hazard ratio 1·9, P < 0·001). Viral load was suppressed in 48-52% of the cohort, with no significant change over the years (P = 0·398). Analysis of TIER.Net data over time provides enhanced insights into the performance of the paediatric ART programme and highlights interventions to improve programme performance.

Reduction in extrapulmonary tuberculosis in context of antiretroviral therapy scale-up in rural South Africa.

Scale-up of antiretroviral therapy (ART) for human immunodeficiency virus (HIV) infection has reduced the incidence of pulmonary tuberculosis (PTB) in South Africa. Despite the strong association of HIV infection with extrapulmonary tuberculosis (EPTB), the effect of ART on the epidemiology of EPTB remains undocumented. We conducted a retrospective record review of patients initiated on treatment for EPTB in 2009 (ART coverage <5%) and 2013 (ART coverage 41%) at four public hospitals in rural Mopani District, South Africa. Data were obtained from TB registers and patients' clinical records. There was a 13% decrease in overall number of TB cases, which was similar for cases registered as EPTB (n = 399 in 2009 vs. 336 in 2013; P < 0·01) and for PTB (1031 vs. 896; P < 0·01). Among EPTB cases, the proportion of miliary TB and disseminated TB decreased significantly (both P < 0·01), TB meningitis and TB of bones increased significantly (P < 0·01 and P = 0·02, respectively) and TB pleural effusion and lymphadenopathy remained the same. This study shows a reduction of EPTB cases that is similar to that of PTB in the context of the ART scale-up. The changing profile of EPTB warrants attention of healthcare workers.

Anti-retroviral Therapy Based HIV Prevention Among a Sample of Men Who Have Sex with Men in Cape Town, South Africa: Use of Post-exposure Prophylaxis and Knowledge on Pre-exposure Prophylaxis.

Men who have Sex with Men (MSM) have been affected disproportionately by the global HIV pandemic. Rates of consistent condom-use are low and there is a need for further biomedical prevention interventions to prevent new HIV infections. Post exposure prophylaxis (PEP) can reduce the risk of HIV, but uptake among MSM is low. Pre-exposure prophylaxis (PrEP), an innovative anti-retroviral-based HIV prevention tool might be an appropriate intervention for MSM who have recently accessed PEP that involves HIV negative individuals taking daily tenofovir+emtricitabine for HIV prevention. 44 MSM, attending a primary health-care level MSM-focused sexual health clinic in Cape Town, South Africa, who had initiated PEP were enrolled in this study. Participants were followed up after 2, 4 and 12 weeks. Self-administered electronic surveys were completed at the initial, 4 and 12 week visit. Barriers and facilitators to accessing PEP and remaining adherent were examined, as was knowledge about PrEP. Thirty-two participants (80 %) were <40 years of age (range 20-65 years). 35 % of the participants reported their reason for requiring PEP as condomless receptive anal intercourse. A further 20 % required PEP following condomless penetrative anal intercourse; 27.5 % required PEP due to a broken condom during receptive anal sex and 2 participants during insertive anal sex. Three participants did not complete 28 days of PEP or were lost to follow up. Over half (58.5 %) of the participants reported being completely adherent to their regime; under a third (31.7 %) reported missing one PEP dose; and 9.8 % reported missing more than one dose. 36/40 (90 %) had heard of PrEP and 30/40 (75 %) indicated that they would use PrEP if it were accessible to them. That we enrolled 44 MSM who accessed PEP from a Department of Health affiliated clinic over 12 months, speaks to the low uptake by MSM of PEP services in South Africa. Adherence was high and demonstrates that adherence support is feasible from a state health clinic. Reported risk behaviors in some high-risk participants did not change over time, demonstrating the need for additional longer-term HIV preventions such as PrEP. PEP users could conceivably be transitioned from PEP to PrEP.

Knowledge, Attitudes and Beliefs regarding Post Exposure Prophylaxis among South African Men who have Sex with Men.

The Soweto Men's Study (2008), demonstrated an overall HIV prevalence rate of 13.2 %, with 10.1 % among straight-identified Men-who-have-sex-with-men (MSM), 6.4 % among bisexual-identified MSM and 33.9 % among gay-identified MSM. Behavioral interventions are imperative, but insufficient to prevent new HIV infections. Biomedical prevention of HIV offers a variety of combination prevention tools, including Post-exposure prophylaxis (PEP). PEP studies amongst MSM have been conducted in Amsterdam, Brazil and San Francisco, but never before in Africa. A cross-sectional, Internet-based survey was initiated to measure knowledge, attitudes and beliefs regarding PEP among South African MSM. Recruitment commenced in June 2014 and ran until October 2015. Participants were recruited through banner advertisements on Facebook.com and mambaonline.com, advertisements in the local gay media and at Health4Men (H4M) MSM-targeted clinics. Outreach workers distributed flyers advertising the study in their local communities. The survey was also made available on a computer at the H4M clinics in Cape Town and Johannesburg to reach MSM who may not have Internet access. A total of 408 men completed the survey. The majority of these men were under the age of 40, identified as gay/homosexual and were employed; 51 % (208/408) self-identified as black or of mixed race. In multivariate analysis participants who identified as gay had greater odds of having previously heard of PEP (AOR 1.91, 95 % CI 1.04, 3.51; p = 0.036), as did those who reported their HIV status as positive (AOR 2.59, 95 % CI 1.47, 4.45; p = 0.001). Participants with medical insurance had greater odds of having used PEP previously (AOR 2.67, 95 % CI 1.11, 6.43; p = 0.029). Bivariate analysis showed that condomless sex in the past 6 months was not significantly associated with PEP knowledge (p = 0.75) or uptake (p = 0.56) of PEP. Our findings suggest a lack of PEP knowledge and uptake among non-gay identified, HIV negative and un-insured MSM. Focusing PEP programs on these men may potentially increase uptake. Increased knowledge needs to be provided to MSM who engage in risky sexual behaviors.

CARD9 in the pathogenesis of axial spondyloarthritis.

Axial spondyloarthritis (axSpA) has been long classified as an autoimmune disease caused by a breakdown in the ability of the immune system to delineate self from foreign, resulting in self-reactive T cells. The strong genetic association of HLA-B27 supports this role for T cells. More recently, genetic and clinical studies indicate a prominent role of the environment in triggering axSpA, including an important role for microbes and the innate immune response. As an example, mutations in genes associated with innate immunity, including the anti-fungal signaling molecule Caspase recruitment domain-containing protein 9 (CARD9), have been linked to axSpA susceptibility. Thus, current thought classifies axSpA as a "mixed pattern condition" caused by both autoimmune and autoinflammatory mechanisms. The goal of this review is to convey.

Where have we come from and where are we going? The paediatric HIV programme in Johannesburg, South Africa, from 2004 to 2018: A retrospective analysis of programme trends.

BACKGROUND: The paediatric HIV treatment programme in South Africa (SA) has grown since its inception in 2004. Despite this impressive scale-up of antiretroviral therapy (ART) in children, the proportion of children started on ART and retained in care remains unacceptably low, with only 47% of the 340 000 HIV-positive children in SA on ART in 2020. Johannesburg is one of the districts in SA with the largest number of children living with HIV who are not on ART, and is a priority district for paediatric case finding and retention. OBJECTIVES: To describe the dynamics of the paediatric HIV programme in Johannesburg, SA. METHODS: A secondary analysis was conducted on patient-level HIV treatment data from TIER.Net, the nationally mandated HIV/ART database. Children aged <15 years who received ART between January 2004 and June 2019 at public health facilities in Johannesburg were included. We reported the number of children on ART and the number who entered and exited the programme by age group over time, and analysed the trends of these indicators. RESULTS: By December 2018, 7 630 children aged <15 years remained in Johannesburg's paediatric ART programme: 82.5% were aged 5 - <15 years, with 54.1% of these being 10 - <15 years old. During the study period, 19 850 children were newly initiated on ART. New initiations slowed from 2013, to range from 1 172 to 1 373 yearly. In 2018, 34.2% of initiators were aged <1 year, 24.2% 1 - <5 years and 41.6% 5 - <15 years. Despite these initiations, the number of children on ART only grew by 97 in 2018, owing to programme losses. In 2018, 924  children (12.1%) aged out, 35 (0.5%) died and 983 (12.9%) were lost to follow-up (LTFU), the latter having increased from 10.7% in 2017. Of children who aged out of the paediatric ART programme, 56.3% remained in care at the same facility. CONCLUSION: Early in the SA ART roll-out, many children were found to be HIV infected and started on ART. This number started to slow in 2013, after which the growth rate of the paediatric HIV programme also began to slow. Scale-up of methods for identifying older children with HIV is needed. While ageing out of the paediatric programme is a consideration, the number of children LTFU remains unacceptably high. Further interrogation of barriers to paediatric retention is needed to help realise the Joint United Nations Programme on HIV and AIDS (UNAIDS) 90:90:90 goals for children in SA.

Primary healthcare workers at risk during COVID-19: An analysis of infections in HIV service providers in five districts of South Africa.

BACKGROUND: Protecting healthcare workers (HCWs) from COVID-19 is a global priority. Anova Health Institute (Anova) is the PEPFAR (US President's Emergency Plan for AIDS Relief) District Support Partner for the Johannesburg, Cape Town, Sedibeng, Capricorn and Mopani districts in South Africa, operating in public sector primary healthcare facilities. At the time of the emergence of COVID-19, Anova employed close to 4 000 people: 41% community health workers (CHWs), 23% data staff, 20% nurses and doctors, 12% management/support and 5% allied HCWs. OBJECTIVES: To describe rates of COVID-19 diagnosis in Anova-employed HCWs in five districts. METHODS: Employees exposed to, tested for or diagnosed with COVID-19 were required to report the event. These reports were compiled into a database to monitor the impact of COVID-19 on the workforce. We kept a timeline of key events occurring at national and district level, including Anova's policies and their implementation, that was used to describe organisational response. We described the number of confirmed cases, cumulative incidence rates and testing rates, broken down by district and job category. We estimated expected deaths and the effect on time off work. RESULTS: Of Anova employees, 14% (n=562) were diagnosed with COVID-19 by the end of September 2020. Cumulative incidence was highest in Sedibeng (29%) and lowest in Mopani (5%). All HCWs experienced high incidences: data staff 17%, allied HCWs 16%, CHWs 14%, nurses and doctors 13%, and management/support 11%. At the peak of the epidemic, for 5 weeks, >5% of employees were unable to work owing to exposure or infection, significantly disrupting service delivery. The additional administrative burden on managers was substantial. CONCLUSIONS: It is critical that all cadres of HCWs are protected in the workplace, including in primary care settings, where better structuresare needed to perform risk assessments and conduct outbreak investigations. CHWs and data staff may be at higher risk owing to poor infrastructure, limited power to negotiate working conditions, and limited experience of infection prevention and control. Their working conditions must be improved to reduce their risk.

Effect of COVID-19 on HIV, tuberculosis, and prevention of mother-to-child transmission of HIV indicators in Mopani district, South Africa.

BACKGROUND: To prevent the spread of SARS-CoV-2, many countries instituted lockdown measures. As the virus was initially slow to spread to rural areas in South Africa, Mopani district in Limpopo Province did not experience a high incidence of COVID-19 until the second wave in December 2020. Until then, lockdown measures were more likely than SARS-CoV-2 infections to have an adverse impact on health services. OBJECTIVES: To analyse HIV, tuberculosis (TB) and prevention of mother-to-child transmission of HIV (PMTCT) indicator trends in Mopani during the COVID-19 lockdown and two COVID-19 waves. METHODS: Using monthly data from the District Health Information System from February 2019 to December 2020, we conducted a retrospective review of data elements and indicators that fall into the following domains: primary healthcare head count (HC), HIV, antiretroviral treatment (ART), PMTCT and TB. Aggregated data were analysed, and an interrupted time series analysis was conducted. We assessed percentage changes between the January - March 2020 and April - June 2020 periods, and differences in means for the period April - December 2019 v. the period April - December 2020 were assessed for statistical significance. RESULTS: At the start of the first wave in April 2020, a statistically significant decline of 10% was recorded for total HC utilisation rates (p=0.1). We also found declines of 665 HIV tests (from 1 608 to 942) and 22 positive HIV tests (from 27 to 4) for children between the ages of 18 months and 14 years (p=0.05), with no recovery. Significant declines were also recorded for children aged <15 years starting (change from 35 to 21) and remaining (change from 4 032 to 3 986) on ART, as well as for adults starting ART (change from 855 to 610) at the onset of the first wave (p=0.01). No significant change was detected in PMTCT and TB indicators during the first wave. Pronounced decreases in HC were recorded in December, during the country's second wave (change from 237 965 to 227 834). CONCLUSION: Declines were recorded for most indicators in Mopani, with HC being affected the most at the start of the first wave and not showing any significant recovery between waves. Strategies are required to mitigate the effects of future COVID-19 waves and encourage positive health-seeking behaviour.

Hopes, fears, knowledge and misunderstandings: responses of HIV-positive mothers to early knowledge of the status of their baby.

Little is known about how HIV-positive mothers experience and react to knowing the HIV status of their baby as diagnosed by the polymerase chain reaction (PCR) test at 4-6 weeks. This qualitative study drew on interviews with 20 mothers of HIV-negative and 18 mothers of HIV-positive babies after receiving their baby's PCR results. Thematic analysis combined exploration of themes that appeared significant to the participants and those relevant to health care. Amongst the themes identified were the following: The period before getting the results involved active mental preparation and was emotionally stressful. Most women accepted the results, but some had doubts about their reliability. Mothers of HIV-negative babies were relieved, but mothers of HIV-positive babies were generally very distressed and expressed a sense of responsibility and guilt. Both groups of mothers had similar hopes for the future of their babies, but the timelines of mothers of HIV-positive babies tended to be shorter. Most women experienced significant levels of stress, but were able to call on support networks and use various individual coping mechanisms to manage their stress. Most women were formula feeding their babies, but regretted not being able to breastfeed. Many women had not planned their current baby and most did not intend to have more children, but many of the latter had not taken active steps to prevent further pregnancy. The findings provide pointers to shortcomings in health worker communication and suggest that more effective communication should take account of normative community views and be more closely attuned to the changing needs and experiences of HIV-positive mothers.

"They see you as a different thing": the experiences of men who have sex with men with healthcare workers in South African township communities.

OBJECTIVES: To describe interactions between men who have sex with men (MSM) and healthcare workers (HCW) in peri-urban township communities in South Africa. METHOD: Qualitative study using semistructured in-depth interviews and focus group discussions in the Gauteng province townships of Soweto and Mamelodi. 32 MSM were purposively sampled for in-depth interviews and 15 for focus group discussions. Topics explored included identity, sexuality, community life, use of health services and experiences of stigma and discrimination. RESULTS: MSM felt their options for non-stigmatising sexual healthcare services were limited by homophobic verbal harassment by HCW. Gay-identified men sought out clinics with reputations for employing HCW who respected their privacy and their sexuality and challenged those HCW who mistreated them. Non-gay-identified MSM presented masculine, heterosexual identities when presenting for sexual health problems and avoided discussing their sexuality with HCW. CONCLUSIONS: The strategies MSM employ to confront or avoid homophobia from HCW may not be conducive to sexual health promotion in this population. Interventions that increase the capacity of public sector HCW to provide appropriate sexual health services to MSM are urgently needed.

Application opportunities of geographic information systems analysis to support achievement of the UNAIDS 90-90-90 targets in South Africa.

In an effort to achieve control of the HIV epidemic, 90-90-90 targets have been proposed whereby 90% of the HIV-infected population should know their status, 90% of those diagnosed should be receiving antiretroviral therapy, and 90% of those on treatment should be virologically suppressed. In this article we present approaches for using relatively simple geographic information systems (GIS) analyses of routinely available data to support HIV programme management towards achieving the 90-90-90 targets, with a focus on South Africa (SA) and other high-prevalence settings in low- and middle-income countries. We present programme-level GIS applications to map aggregated health data and individual-level applications to track distinct patients. We illustrate these applications using data from City of Johannesburg Region D, demonstrating that GIS has great potential to guide HIV programme operations and assist in achieving the 90-90-90 targets in SA.

Hepatitis C: A South African literature review and results from a burden of disease study among a cohort of drug-using men who have sex with men in Cape Town, South Africa.

BACKGROUND: Hepatitis C virus (HCV) is a chronic infection of increasing importance, especially among people living with HIV/AIDS. Co-infection with HIV can accelerate progression of HCV liver disease to cirrhosis and end-stage liver failure and elevate the risk of hepatocellular carcinoma. Globally, men who have sex with men (MSM) and people who inject drugs are at increased risk of HCV infection compared with the general population. Few studies on HCV in these key populations have been done in South Africa (SA). OBJECTIVE: To describe the disease burden of HCV in drug-using MSM who attend harm-reduction services at the Anova Health Institute's Health4Men clinic in Cape Town, SA. METHODS: In 2012 - 2014, attendees of an MSM-focused harm-reduction programme were invited to participate in our study. After informed consent, participants completed a brief demographic questionnaire and underwent phlebotomy for anti-HCV antibody, hepatitis B virus (HBV) surface antigen and surface antibody testing. Participants received counselling and education with regard to their results. HIV status was extracted from the case notes of participants who had previously been tested at the study site. Data were analysed using standard statistical techniques. RESULTS: Forty-one MSM were enrolled - 11 (27.0%) tested anti-HCV antibody-positive, indicating prior exposure to HCV or chronic infection; 10/11 (91.0%) were positive for HBV surface antibodies, suggesting previous HBV exposure or vaccination; and 1 (2.0%) screened positive for HBV. Of the HCV-seropositive individuals, HIV status was known in 8/11; 3/8 (37.5%) were HIV-positive. CONCLUSION: We demonstrated a high burden of HCV exposure or infection among a small urban cohort of MSM who inject drugs. We recommend active screening of MSM (especially those who report drug use) for HCV, and the development of referral networks for access to treatment.

Global emissions of terpenoid VOCs from terrestrial vegetation in the last millennium.

We investigated the millennial variability (1000 A.D.-2000 A.D.) of global biogenic volatile organic compound (BVOC) emissions by using two independent numerical models: The Model of Emissions of Gases and Aerosols from Nature (MEGAN), for isoprene, monoterpene, and sesquiterpene, and Lund-Potsdam-Jena-General Ecosystem Simulator (LPJ-GUESS), for isoprene and monoterpenes. We found the millennial trends of global isoprene emissions to be mostly affected by land cover and atmospheric carbon dioxide changes, whereas monoterpene and sesquiterpene emission trends were dominated by temperature change. Isoprene emissions declined substantially in regions with large and rapid land cover change. In addition, isoprene emission sensitivity to drought proved to have significant short-term global effects. By the end of the past millennium MEGAN isoprene emissions were 634 TgC yr-1 (13% and 19% less than during 1750-1850 and 1000-1200, respectively), and LPJ-GUESS emissions were 323 TgC yr-1(15% and 20% less than during 1750-1850 and 1000-1200, respectively). Monoterpene emissions were 89 TgC yr-1(10% and 6% higher than during 1750-1850 and 1000-1200, respectively) in MEGAN, and 24 TgC yr-1 (2% higher and 5% less than during 1750-1850 and 1000-1200, respectively) in LPJ-GUESS. MEGAN sesquiterpene emissions were 36 TgC yr-1(10% and 4% higher than during 1750-1850 and 1000-1200, respectively). Although both models capture similar emission trends, the magnitude of the emissions are different. This highlights the importance of building better constraints on VOC emissions from terrestrial vegetation.