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Unit 1: Introduction to STI Surveillance in Africa and the Relationship between STIs and HIV #4-1-1.

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Presentation on theme: "Unit 1: Introduction to STI Surveillance in Africa and the Relationship between STIs and HIV #4-1-1."— Presentation transcript:

1 Unit 1: Introduction to STI Surveillance in Africa and the Relationship between STIs and HIV #4-1-1

2 Warm Up Questions: Instructions v Take five minutes now to try the Unit 1 warm up questions in your manual. v Please do not compare answers with other participants. v Your answers will not be collected or graded. v We will review your answers at the end of the unit. #4-1-2

3 What You Will Learn v By the end of this unit you should be able to: © describe the three main areas of inter- relationship between STIs and HIV © describe the basic principles of the Integrated Disease Surveillance system © explain how an STI increases susceptibility to HIV #4-1-3

4 What You Will Learn, Cont. v By the end of this unit you should be able to: © explain how an STI increases the risk of transmitting HIV © Describe how STI surveillance data can be used in understanding HIV epidemics #4-1-4

5 STIs in Africa v Sexually transmitted infections (STIs) are diseases that are spread from person to person during sexual contact. v The impact of these diseases is made worse by their role in spreading HIV. #4-1-5

6 Definitions v Incidence: the number of new infections in a given time period v Prevalence: the proportion of a population with a disease or condition at a point in time #4-1-6

7 Table 1.1. STI Prevalence and Incidence Estimates, 1999 #4-1-7Source: WHO, 1999 Region Pop yrs (millions) Cases (millions) Prevalence per 1000 Ann. Incid. (millions) North America Western Europe North Africa & Middle East Eastern Europe & Central Asia Sub-Saharan Africa South & South East Asia East Asia & Pacific Australia & New Zealand Latin America & Caribbean Total

8 Table 1.2. State of HIV Epidemic and Benefit of STI Surveillance #4-1-8 For this state of HIV epidemic…STI surveillance serves as: Low-level: HIV prevalence has not consistently exceeded 5% in any group.  an early warning system for HIV infection and emergence of HIV in new groups or new geographical areas  an evaluation tool for HIV prevention programmes Concentrated: HIV prevalence consistently >5% in one or more groups with high-risk behaviour. HIV prevalence <1% in pregnant women.  a marker for the emergence of HIV in new groups  a marker of how successful prevention programs have been in high-risk populations Generalised: HIV prevalence is consistently >1% in pregnant women.  a marker of how successful prevention programs have been in the general population

9 Types of Case Reporting v Two different methods for reporting STI cases: © aetiologic case reporting, using laboratory results that identified the specific microbial organism that caused the STI © syndromic case reporting, using a set of clinical signs and symptoms that correspond to a clinical syndrome. The syndromes include:  Male and female genital ulcer disease  Male urethral discharge v Most African countries lack resources for aetiologic reporting. Syndromic reporting is thus more practical. #4-1-9

10 Additional STI Surveillance Activities #  In addition to case reporting, the following activities are part of STI surveillance: © monitoring aetiologies for STI syndromes © assessing prevalence of certain STIs in the general population and in sub-populations © combining behavioural surveys with STI and HIV testing © measuring anti-microbial resistance patterns

11 Problems with STI Surveillance v The lack of STI surveillance means there is not enough information for STI and HIV programmes. v In some countries, STI surveillance is integrated into the general disease surveillance system. This is less costly, but the data are less detailed. v In other countries, STI surveillance takes place through a vertical system. While more expensive, the data are higher quality. #4-1-11

12 Passive and Active Surveillance v In a passive surveillance system, health facilities provide case reports directly. v In an active surveillance system, public health officers contact health facilities, identify and report cases. v Passive surveillance results in under- reporting, but active surveillance can be very costly and thus impractical in Africa. #4-1-12

13 How Integrated Disease Surveillance Improves STI Surveillance v The IDS strategy integrates: © priority communicable disease surveillance activities at the district level © support for training, supervision and resources v IDS includes surveillance of: © urethral discharge syndrome in men © genital ulcer disease in women and men #4-1-13

14 v IDS improves STI surveillance by: © simplifying disease reporting for communicable diseases of the highest priority © combining data management and analysis at the district and national levels for priority communicable diseases © providing training, supervision and resources for surveillance for all disease control programmes # How Integrated Disease Surveillance Improves STI Surveillance

15 STI and HIV Inter-relationships v The 3 main inter-relationships between STIs and HIV are: © Behavioural factors – Both STIs and HIV can be sexually transmitted. © Epidemiological factors – Populations with high rates of STIs have high rates of sexually transmitted HIV. © Host factors – The presence of STIs cause changes in the immune system in the body’s mucous membranes, making it easier to get and spread HIV. #4-1-15

16 How HIV is Transmitted v What risk factors determine whether STIs or HIV will be transmitted through a sexual exposure? v How does the presence of an STI affect those factors in HIV-infected and uninfected persons? v We will consider three main biological factors: © the amount of virus to which an uninfected person is exposed © the type of exposure © host factors that protect uninfected persons #4-1-16

17 Amount of Virus v The amount of virus in the body is called the viral load, and can be measured with a blood test. v The viral load in an HIV-infected person varies during the course of the disease. v Antiretroviral therapy lowers the viral load in blood and possibly genital fluids. v An uninfected person is more likely to become infected if they are exposed to fluids with high viral loads. #4-1-17

18 Type of Exposure v Exposure of an uninfected person’s blood to an infected person’s blood is more dangerous than exposure to other body fluids. v Sexual exposure risk is increased by: © the presence of white blood cells and inflammation © the duration of exposure #4-1-18

19 Type of Exposure, Cont. v The risk of exposure from a man to a woman is higher than that from a woman to a man. © Semen can remain viable in the vagina for 72 hours after ejaculation. © Vaginal fluids do not usually enter the male partner’s urethra. © Cervix has a larger surface area than the male urethra. #4-1-19

20 Figure 1.1. HIV Infection Process #4-1-20

21 Figure 1.1. HIV Infection Process, Cont. #4-1-21

22 Figure 1.2. How STIs Increase the Risk of HIV Transmission #4-1-22

23 Table 1.3. The Effect of STIs on HIV- Infected & HIV-Uninfected Patients Patient’s HIV Status Effect of STIs Infected  Increases the number of HIV-infected white blood cells to the surface of mucous membranes Uninfected  Increases the number of white blood cells that can then be infected by HIV  Destroys the epithelial layer through ulceration, exposing the submucosal layer that contains target cells that can be infected by HIV #4-1-23

24 Can Controlling STIs Decrease HIV Transmission? v In the Mwanza district of Tanzania, HIV incidence was 42% lower in communities with enhanced STI services compared to areas with the usual services. v Two studies in Uganda did not confirm this pattern. v Difference might be due to the type of epidemic in each area. The epidemic in Tanzania was expanding rapidly, while the Ugandan epidemic was stable. #4-1-24

25 Treatment Implications v You can help clinicians reduce patients’ risk of transmitting and acquiring HIV by training them to: © provide HIV behavioural risk-reduction counselling and testing to all patients diagnosed with an STI © screen HIV-infected patients for STIs © treat both symptomatic and asymptomatic STIs © treat sexual partners #4-1-25

26 In Summary v STIs and HIV are inter-related because of behavioural, epidemiological and host factors. v STIs increase susceptibility to HIV and also increase the risk of transmitting HIV. v STI surveillance data can be used as an early warning of the emergence of HIV and as an evaluation tool for HIV prevention programmes. #4-1-26

27 Warm Up Review v Take a few minutes now to look back at your answers to the warm up questions at the beginning of the unit. v Make any changes you want to. v We will discuss the questions and answers in a few minutes. #4-1-27

28 Answers to Warm Up Questions 1. What are the three main areas of inter- relationship between STIs and HIV? #4-1-28

29 Answers to Warm Up Questions 1. What are the three main areas of inter- relationship between STIs and HIV? Behavioural, epidemiological and immunological #4-1-29

30 Answers to Warm Up Questions, Cont. 2. True or false? You can reduce the risk of patients transmitting and acquiring HIV infection by controlling STIs. #4-1-30

31 Answers to Warm Up Questions, Cont. 2. True or false? You can reduce the risk of patients transmitting and acquiring HIV infection by controlling STIs. True #4-1-31

32 Answers to Warm Up Questions, Cont. 3. True or false? An STI surveillance system can serve as an evaluation tool for HIV prevention programmes. #4-1-32

33 Answers to Warm Up Questions, Cont. 3. True or false? An STI surveillance system can serve as an evaluation tool for HIV prevention programmes. True #4-1-33

34 Answers to Warm Up Questions, Cont. 4. List two ways the IDS strategy is expected to improve STI surveillance. #4-1-34

35 Answers to Warm Up Questions, Cont. 4. List two ways the IDS strategy is expected to improve STI surveillance. a. combining communicable disease priority surveillance activities at the district level b. supporting training, supervision and resources for all disease control programmes #4-1-35

36 Answers to Warm Up Questions, Cont. 5. Which of the following increases the risk of HIV transmission in sexual exposure? a. greater mucous membrane exposure b. the presence of blood and inflammation c. increasing the duration of exposure d. all of the above #4-1-36

37 Answers to Warm Up Questions, Cont. 5. Which of the following increases the risk of HIV transmission in sexual exposure? a. greater mucous membrane exposure b. the presence of blood and inflammation c. increasing the duration of exposure d. all of the above #4-1-37

38 Answers to Warm Up Questions, Cont. 6.Which of the following determines infectivity of HIV? a.the amount of virus (viral load) to which an uninfected person is exposed b.the type of exposure (blood, mucous membrane) c.host factors that protect against infection d.all of the above #4-1-38

39 Answers to Warm Up Questions, Cont. 6.Which of the following determines infectivity of HIV? a.the amount of virus (viral load) to which an uninfected person is exposed b.the type of exposure (blood, mucous membrane) c.host factors that protect against infection d.all of the above #4-1-39

40 Small Group Discussion: Instructions v Get into small groups to discuss these questions. v Choose a speaker for your group who will report back to the class. #4-1-40

41 Small Group Reports v Select one member from your group to present your answers. v Discuss with the rest of the class. #4-1-41

42 Case Study: Instructions v Try this case study individually. v We’ll discuss the answers in class. #4-1-42

43 Case Study Review v Follow along as we go over the case study in class. v Discuss your answers with the rest of the class. #4-1-43

44 Questions, Process Check v Do you have any questions on the information we just covered? v Are you happy with how we worked on Unit 1? v Do you want to try something different that will help the group? #4-1-44


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