Chlamydiainfection: Transmission, causes, risk factors and preventionChlamydiainfection: Transmission, causes, risk factors and prevention Chlamydiatrachomatis is a gram-negative bacterium that is often don’t show any specificsymptoms but could lead to serious conditions if left untreated likePID aka pelvic inflammatory disease, epididymo-orchitis and infertility1Genital chlamydia is the most common sexually transmitted infectionin men and women accounting for 46.1 percent of all STIs diagnosedin 2015.
1 Women are more likely to get Chlamydia than mendue to multiple reasons like social and anatomical vulnerability. This will bediscussed more further down Current studies suggest factorsthat increase the risk of a person contracting Chlamydia areyoung age (under 25), multiple partners, previous sexually transmittedinfection (STI), socioeconomic status, incorrect use of condoms,substance abuse, high alcohol intake (as marker of risk takingbehaviour) and men who have sex with men. Since many chlamydialinfections are asymptomatic, the most effective prevention tacticwould be routine screening of high-risk individuals.
A Nationalchlamydia screening programme (NCSP) was developed in response to highnumber of cases in people under 25. NCSP reduced untreated chlamydia casesand transmission but prevalence of chlamydia managed to stay high due to numberof reasons, one of them being partners not being correctly notified. Gonorrhoeaand the rise of antibiotics resistanceGonorrhoeais an STI caused by Neisseria gonorrhoeae bacterium and for most people it’s anasymptomatic infection. The primary mode oftransmission is through unprotected vaginal, oral or anal sex. It couldeventually lead to infertility if left untreated.
It also causescomplications like PID in women and inflammation of the epididymis, prostategland, and urethra in men. It is treated with antibiotics but current research hasshown strains of this bacteria has acquired resistance to several antibioticsover the last 10 years. Gonorrhoea is most commonly seen in age group 24-25 with a rate of 269.5 per 100,000 population in 2015. Itis also the second most common STI after chlamydia in the United Kingdom. Thesestatistics raise serious concern as ‘super-gonorrhoea’ spread across thecountry.
According to World Health Organisation (WHO), we need betterprevention, treatment, early diagnosis and complete tracking of new infections.Gonorrhoea has a social stigma attached to it like any otherSTI so patients are reluctant to inform their partners themselves and rely on providerreferral services by health advisors. SyphilisSyphilis is caused by the bacteriumTreponema pallidum.
5 The primary mode oftransmission is by sexual contact, and the next most common is from mother tofoetus in-utero.(5,6) Syphilis isdivided into several stages according to its different signs and symptoms.5 Primarysyphilis is associated with sores around mouth or genitals whilst secondarystage is associated with rash, swollen lymph nodes and fever.
7 The early stages(primary, secondary, and early latent) are the most infectious and the tertiarystage is the most harmful as it causes multiple organ damage.7 Although thenumber of diagnosis were not as big as for other STIs, it did represent thehighest increase of any STI in 2015. (5,6) Men aged 25-34 (45 per 100,000population) and 35-44 (39.1 per 100,000 population) represented the highestrate of diagnoses in 2015. Males accounted for 94 percent of all syphilisdiagnoses and men who have sex with men accounted for 79.4 percent.(5,6)Partner notificationstudies have shown that the rate of transmission of primary, secondary, andearly latent syphilis is around 60 percent.5Partnernotification: Provider referral and patient referralPartner notification (PN) if donecorrectly treats infection on time, reduces recurrent infection and mayeventually contribute to an overall reduction of that infection in thecommunity.
Patient are offered a few choices when it comes to partner notification.A lot of times, patient take the task of informing their partners themselvesrather than giving their partners’ details to health advisors. This approach ofPN is called patient referral. Patient referral is the most common approach toPN but results show less than half the patients actually notify their partnersaccording to a study done on ‘Anticipated versusactual partner notification following STI diagnosis among men who have sex withmen and/or with transgender women in Lima, Peru’.9 The study showed among allsexual partners, 35 percent were notified of the STI diagnosis, though only 51percent of predicted PN occurred and 26 percent of actual notifications wereunanticipated.
47 percent of participants notified no partners, while 24percent notified all partners. Patient referral is more common in stablerelationship than casual.9 There havebeen studies done which shows that patient referral (where patient takes on thetask of telling their partners themselves) could be more effective if cliniciansgive patients some kind of written information, sampling kits or medication totake it to their partner(s) with them. This is known as expedited partnertherapy or EPT.13 Since prescribing drugs with patient consultation is notallowed in UK, accelerated partner therapy (APT) is being used where after atelephone consultation, partners can have access to treatment or sampling kitsfrom either GUM clinic or pharmacy.13There has been evidencethat PN done via APT or EPT has managed to reduce re-infection in cases byalmost 30 percent according to a systematic review done recently. Although thisis a good increase, it wasn’t significantly better than EPR aka enhancedpartner referral.
Men who have sex with men have further web-based help wheretheir partners are informed anonymously.13 The systematic review also confirmedthat a pre-planned follow-up call to the patient also help as then theclinician can provide them with the option of provider referral again ifpatient was unsure during their face-to-face meeting.13The stigma behind contracting an STIcould make the experience of informing the partners rather traumatic forpatients. Due to this, patients often don’t notify their partners out of fearfor their safety or reputation. Thiswhere provider referral comes into play.
Provider referral is another approachto partner notification. It is a service provided to patients where healthadvisers contact their past or present partner(s) for them without revealingthe patient’s identity and inform them of their possible exposure so they couldseek medical care.13 Latest studieshave found that provider referral is more frequently requested for casualpartners, for whom the onward transmission rate is higher.
The resultsshow that number of partners of who need to be treated to stop transmission ofan STI is 1:1 for casual partners, compared with 2:5 for regular partners. Providerreferral is usually undertaken by a specialist sexual health adviser based in asexual health clinic, and recent guidelines recommend that this approach ismade available wherever STIs are diagnosed through the development of acommunity-based partner notification service.8Timely partner notification is key toreducing the spread of infection in the community. It also protectsunsuspecting partners from long-term tissue damage from an untreated infection.
Doespartner notification work?Studies have shown that newinterventions like APT, EPT and EPR works more effectively if patiets are givenwritten information and sampling kits for their partners. PN is more likely tomore better for those in long term relationship so it only reaches a proportionof contacts often missing casual partners. Mathematicalmodels suggest that improving partner notification could be highlycost-effective in terms of cost per infection diagnosed when compared withexpanding coverage of screening, for example.8Britishassociation for sexual health and HIV and history takingIn 2013, the British Association ofSexual Health and HIV (BASHH) published guidelines to outline the minimumrequirements of practice during a routine sexual history consultation.1 Thisincluded specific guidance for information obtained regarding recent sexualpartners to aid risk assessment. It is recommend that all patients should beasked the following: gender of partner, sites of exposure, use of barriermethods, relationship to partner and symptoms or high risk behaviour of this partner.1At a minimum, the number of partners within the past 3 months should berecorded, with specific details for a minimum of the last 2 partners if theseare within the past 3 months.
1 When considering high risk behaviours it isknown that the circumstance or site at which partners are met can incur higherrisk for acquisition of sexually transmitted infection. This information haspreviously been utilised by public health to guide health promotion activitiesand condom distribution.2 NICE guidance highlights specific high-risk premisesfor sexually transmitted infection include commercial venues including sex onpremises venues, public sex environments and other places where people are mostat risk of STI.
It is important as part of routine sexual history taking thatthis information is obtained to inform initial testing and any health promotionactivities.Prevalenceof Sexually transmitted infections in young adultsMen and women under 25 years old are atthe greatest risk of acquiring an STI for several reasons. The main one beingthat they are more likely to have unprotected sex with multiple partners. In addition, young people are at greaterrisk for substance abuse and other contributing factors that may increase riskfor STIs.
Althoughoverall rates of gonorrhoea have been declining in the general population forover a decade, this decline has been less pronounced among adolescents than inother age groups. Chlamydial infection has been consistently high among youngadults; in some studies, up to 30-40 percent of sexually active adolescentfemales have been infected. Women are more likely to be infected than menbecause of their increased cervical ectopy. Cervical ectopyrefers to columnar cells, being located on the outer surface of the cervix. Althoughthis is a normal finding in adolescent and young women, these cells are moresusceptible to infection. The higher prevalence of STIs among adolescents mayalso be due to having trouble accessing STI prevention and management serviceslike lack of transportation, long waiting times, clinic hours clashing with schooltime, embarrassment attached to seeking STI services, method of specimencollection, and concerns about confidentiality.
Impactof STDs on women’s healthWomen are biologically more likely to become infected than menif exposed to a sexually transmitted pathogen. Many STIs are transmitted more easily from man to woman thanfrom woman to man. For example, the risk to awoman of getting Gonorrhoea from a single act of intercourse with an infectedmale partner could as high as 60 to 90 percent, while transmission from aninfected woman to man is about 20 to 30 percent.STIs are often asymptomatic in women especiallyin gonorrhoea and chlamydia.
For example, in women with gonorrhoea, 30 to 80percent of them are asymptomatic, while less than 5 percent of men areasymptomatic. Similarly, as many as 85 percent of women with chlamydialinfection are asymptomatic compared to 40 percent of infected. When an STI issuspected, it is often more difficult to diagnose in a woman because theanatomy of the female genital tract makes clinical examination more difficult.
For example, a urethral swab and a Gram stain are sufficient to evaluate thepossibility of gonorrhoea in men, but a speculum examination of the cervix anda specific culture for gonorrhoea have been required for women. Thus, womenwith gonorrhoea or chlamydial infection are often not diagnosed with an STIuntil complications, such as pelvic inflammatory disease, occur. According to the article ‘Disproportionate Impact of SexuallyTransmitted Diseases on Women’ published by CDC, women have a higher risk ofacquiring STI due to social norms and constructs. It says culturally, men are expected to havemultiple sexual partners including sex workers without risking judgement fromtheir social peers while women may feel they would face abuse if they refusesex or ask for protection. This behaviour effectively puts women at higher riskof acquiring STIs. Interrelationbetween sociodemographic and geospatial risk factorsThe main goal of marrying geographicalmapping and epidemiological data is to see if there’s any relation between health issues that impact a largepopulation, and the trends by which these populations are affected. If we findcertain high-risk locations due to these techniques, then better preventionstrategies could be made. Using geographic information systems (GIS) in publichealth provides a strong foundation to monitor any outbreaks and find thesource of infection.
A study byCharles lacey looked at four most common clinically diagnosed sexuallytransmitted infections (STIs) which included gonorrhoea and chlamydia toexamine the degree of demographic and geospatial correlation between theseSTIs. They used details of patients aged 15-25 who attended STI clinic withconfirmed diagnosis of either of the four STIs they were studying. Data wascollected from 1994-1995 from Leeds Healthcare commissioning area. Theycompared aged, sex, socioeconomic status and geospatial distribution of theseSTIs. Regressionanalysis showed that young age (15–24 years), ethnicity (with a gradient ofrisk black >white >Asian), and residence in inner city areas ofdeprivation were independent risk factors for all STDs.
There were highlysignificant correlations in the geospatial distribution of incidence ratesbetween the four infections.Population based studies are needed toclarify whether ethnicity is associated with differing sexual behavioural ormixing patterns. Their datasuggested that chlamydia screening in women <25 years of age could detect70% of cases in the community.
Unifying the geospatial distribution data withtarget population, the study suggested that an intervention could control thespread of even the most common STIs in urban areas. Geographicprofiling in HealthcareGeographic profiling (GP) was initiallyused in locating the perpetrator’s house by accessing his crime sites. Thismodel has been very successful in criminology and has been used all around theworld. The model works by giving hit scores, the percentage of area that needsto be searched to find the perpetrator’s home. For an unprioritised search, onaverage the hit score is 50 percent but for geospatial mapping software atypical hit score in criminology is under 5 percent which is a 10-foldimprovement.
This model has been applied to biologyrecently after its success in criminology. This has been used in epidemiologytoo recently where they used GP to re-analyse a cholera outbreak study of 1854to see if the model found the outbreak source by evaluating the disease sitesas input. It successfully showed ‘The broad street pump’ as the main source ofinfection by ranking it in the top 0.2 percent of the geoprofile. The samemodel was used to analyse malaria cases in Cairo, Egypt and GP againsuccessfully ranked locations of mosquitogenic local water sources which werein the top 2 percent of geoprofile. It obvious that GP is extremely good atlocating sources of infection.
Millions of pounds are spent every yearby local and national agencies on STI interventions and prevention strategies.Allocation of resources requires knowledge of vulnerable groups, effectiveinterventions and the spatial distribution of STIs amongst the populace.Geospatial mapping is beneficial as part of an integrated STI control strategybecause evidence-based targeting of interventions is more efficient,environmentally friendly and cost-effective than untargeted interventions.
3Geospatial analysis of epidemiological and health service data can generatemaps of hotspots—sites where STI prevalence is concentrated. This method ofdata visualisation can allow us to determine where resources and services areinadequate and where they should be installed to achieve the greatest impact.