Gonorrhea and Human Immunodeficiency Virus (HIV) are both infections that can be transmitted via sexual contact. Gonorrhea has been identified as one of the most common Sexually Transmitted Infections (STIs) affecting individuals. From the outset of the HIV epidemic, it was observed that individuals who contracted sexually transmitted diseases (STDs) seemed to have a higher susceptibility to both acquiring and transmitting HIV.¹ Having an STI can increase the risk of sexual transmission of HIV. This article will examine gonorrhea and its association with HIV transmission.

Overview of gonorrhoea

Gonorrhea is caused by the bacterium Neisseria gonorrhoeae.² It is a non-ulcerative STI characterised by localised inflammation and purulent discharge from the urethra or cervix.³ It infects only humans, affecting all age groups, but has a significant impact on young adults.⁴ This bacterium can cause infection in the genitals, rectum and throat.

Symptoms and complications

Gonorrhea frequently shows no symptoms in its early infection.^5,6 The urethra and cervix are the most frequently affected sites.⁷ Gonorrhea can infect extra-genital sites such as the throat, rectum, and eyes in both men and women, and can rarely spread systemically.¹ The symptoms exhibited differ in males and females and vary in individuals. 

Some of the symptoms include:

In male 

1. Burning sensation when urinating 
2. Penile discharge
3. Pain in the testicle

In females 

1. Burning sensation during urination
2. Vaginal discharge
3. Painful sexual intercourse
4. Lower abdominal pain

In females, untreated gonorrhea can spread to infect other reproductive organs, resulting in pelvic inflammatory disease, which can progress to cause infertility. 

Overview of HIV

HIV is caused by the Human Immunodeficiency Virus. This viral infection targets the immune system. The virus primarily attacks CD4+ T-helper lymphocytes, causing severe immune system disruption through the ongoing depletion of these cells.⁸

Symptoms and complications

In the case of HIV, when the immune system is severely compromised, symptoms may include:

• Weight loss
• Chronic diarrhea 
• Night sweats 
• Skin problems 
• Recurrent infections
• Serious life-threatening infection

Causes and transmission

Gonorrhea is transmitted through genital, anal, or oral sex with an infected partner. Newborns can acquire gonorrhea from their infected mothers during delivery.⁹ Gonorrhea spreads through direct contact with infected secretions, making sexually active individuals susceptible. Multiple sexual partners, a history of STIs, and inconsistent condom use increase the likelihood of infection.¹⁰

HIV shares a similar mode of transmission to gonorrhoea. HIV-1 spreads through sexual contact across mucosal surfaces, from mother to infant, and via percutaneous inoculation.¹¹ The likelihood of HIV transmission during sexual activity is influenced by both the infectiousness of the individual with HIV and the susceptibility of their sexual partner.¹²

Epidemiology of gonorrhoea and HIV

Gonorrhea cases are on the rise in many nations. The World Health Organisation estimates that 87 million new gonococcal infections occurred among individuals aged 15-49 years.¹³ According to UNAIDS, an estimated 39 million people were living with HIV worldwide. HIV continues to be a major public health concern globally. 

Biological mechanisms linking gonorrhoea and HIV transmission

In vitro, Neisseria gonorrhoeae (GC) can enhance HIV infection depending on the target cells involved.¹⁴ This genital infection can increase the risk of HIV infection by disrupting the epithelial barrier, attracting HIV target cells to the genital area, or creating a pro-inflammatory environment. In individuals already infected with HIV, these co-infections can raise HIV levels in genital secretions, enhancing the likelihood of transmission to sexual partners.¹⁵

Impact of gonorrhea on the immune system

When the body encounters a gonococcal (Neisseria gonorrhea) infection, it responds by sending inflammatory cells, such as neutrophils, to the site of infection. These cells help to fight off the bacteria and resist its invasion. Additionally, the body initiates an adaptive immune response where specific immune cells present antigens (pieces of the bacteria) to trigger a targeted attack to eliminate the pathogen. However, Neisseria gonorrhoeae has developed several immune escape mechanisms that make it challenging for the body to clear the infection.¹⁶

Inflammation and tissue damage

Inflammation is regarded as the body's natural immune response to infection. STIs like gonorrhea significantly affect the female genital mucosa, a crucial barrier against infections like HIV. When these STI pathogens are detected by receptors on or inside mucosal cells, an inflammatory response is triggered. These mucosal responses can be asymptomatic or lead to discharge. Although these responses aim to eliminate the pathogens, they can sometimes fail or cause damage to the mucosal barrier, making it easier for HIV to access target cells. Neisseria gonorrhoeae triggers Th17-driven inflammatory responses, leading to an influx of neutrophils, while also suppressing Th1 and Th2 adaptive immunity, including antibody responses. This suppression involves TGF-β and regulatory T cells.¹⁷ Additionally, with gonococcal infection, there is an increase in the number of immune cells, which are primary targets for HIV, thus raising the risk of HIV acquisition.¹⁸

Increased susceptibility to HIV

STIs not only enhance HIV-1 shedding in HIV-1-infected adults but also raise the risk of HIV-1 infection in HIV-1-negative individuals.¹⁹

Gonorrhea and increased HIV viral load

Gonorrhea can exacerbate HIV infection by increasing the viral load in individuals who are co-infected with both pathogens. This means that people with both gonorrhea and HIV tend to have higher levels of HIV in their blood and other bodily fluids compared to those with HIV alone. A patient with a high HIV viral load increases the risk of HIV transmission.²³

How gonorrhea facilitates HIV entry and replication

Defensins are antimicrobial peptides; they play a crucial role in the innate defence of mucosal surfaces.²⁰ Human beta-defensin 5 and human beta-defensin 6 are induced in response to Neisseria gonorrhoeae infection. The increased levels of this defensin in the cervicovaginal epithelial cells facilitate HIV entry, thus infecting the host.²¹

Effect on HIV progression

Newer data indicate that certain simultaneous STIs, including gonorrhea, can directly impact the transmission of HIV-1 and potentially influence HIV-1 management, leading to increased susceptibility to AIDS.²² 

Clinical and public health implications

Diagnosis and screening

The intersection between gonorrhea and HIV has significant implications for public health. The diagnosis and treatment of gonorrhea should be a priority in HIV prevention efforts. Prompt diagnosis and treatment of gonorrhea can reduce genital inflammation, lowering the risk of HIV transmission and acquisition. Therefore, routine screening for gonorrhea, especially among high-risk populations, is crucial.    

Treatment strategies

An untreated gonorrhea can increase the chances of transmitting HIV. Prompt treatment of any co-infection, including gonorrhea, is advised. Consistent use of antiretroviral drugs in patients living with HIV is necessary to suppress the HIV viral load and thereby reduce the risk of HIV transmission.

Several prevention strategies are described below:

1. Correct condom use in every sexual encounter can prevent most cases of transmission of HIV
2. Limiting the number of sexual partners can lower the risk of HIV exposure. To curb the spread of the disease, individuals diagnosed with gonorrhea should inform their current and recent sexual partners
3. Regular HIV testing and campaigns
4. Public health campaigns and education

Summary

Gonorrhea is a sexually transmitted infection (STI) caused by the bacterium Neisseria gonorrhea. It primarily affects the urethra, rectum, and throat. If left untreated, it can lead to serious health complications such as pelvic inflammatory disease (PID) and infertility. 

There is a strong association between gonorrhea and HIV transmission. Individuals infected with gonorrhea are at an increased risk of acquiring HIV if exposed to the virus. This is due to several reasons. Disruption of the epithelial barrier prompts the activation of the immune response. Inflammation caused by gonorrhea can make it easier for HIV to enter the body.

Treating gonorrhea promptly and practising safe sex are crucial in reducing the risk of both infections.