[Grace]

Thinking of your current or a past practice area provide an example of the train of transmission specific to that area. Fill in all ‘links’ in the chain with an example for each link:

Infectious Agent:

Reservoirs:

Portals of Exit:

Modes of Transmission:

Portals of Entry:

Susceptible Host:

[Yu]

I work at a long-term care facility, and we recently experienced an enteric outbreak. This course has deepened my understanding of the chain of transmission, and I can now easily relate it to a nursing home setting.
Infectious Agent: Norovirus
Reservoirs: An infected resident or staff member
Portals of Exit: Vomitus or feces
Modes of Transmission: virus is spread via contaminated hands, surfaces (bedrail, call bell, doorknobs)
Portals of Entry: Mouth – Another resident ingests the virus by touching their mouth after contacting contaminated surfaces or consuming contaminated food/water
Susceptible Host: An elderly resident with a weakened immune system or chronic conditions,

[Yiqun]

Hi,Yu

Thank you for your sharing. My workplace had been encountered the enteric outbreak during this winter and it brought lots of pressure to staff when residents were actively symptomatic. Therefore, break the chain of infection is the essential method to ensure the infection was contained and other residents would not catch the virus.

[Semhar]

It is concerning to hear about the Norovirus outbreak in your facility. Outbreaks like these can have significant impacts on residents and staff alike. It is crucial to implement strict infection control measures, such as frequent hand washing, sanitizing surfaces, and implementing proper PPE. Have any specific strategies that have been found effective in managing this situation? It might also be beneficial to review training sessions for staff on proper hygiene protocols and ensure that everyone is aware of the importance of being vigilant during outbreaks. Sharing insights from your experiences could be valuable for others in similar settings. Stay safe.

[Helen]

Knowing the chain of transmission is essential for infection management in long-term care facilities. Through access like the respiratory tract, gastrointestinal system, or skin cracks, the infectious agent—such as bacteria (C. difficile), viruses (Norovirus), or fungus ( Candida) etc.—can invade vulnerable people, who are frequently older individuals with compromised immune systems. Direct contact, droplets, or airborne particles can all spread the disease. Pathogens can live in reservoirs such as contaminated surfaces, medical equipment, or diseased inhabitants. They can also leave the body through respiratory secretions, feces, blood, or urine. Appropriate infection control measures, including as hand washing, cleaning techniques, and wearing personal protective equipment, are essential to halting the spread of illnesses in these settings.

[Adaeze]

Your write-up provides a clear and thorough explanation of the chain of transmission and its importance to infection management in long-term care facilities. You carefully highlighted key elements such as access points for pathogens, modes of transmission, and potential reservoirs, which are crucial for understanding how infections spread.
I also think that educating staff and residents in these facilities about infection prevention protocols, regular training sessions on proper hand hygiene, the correct use of personal protective equipment (PPE), and recognizing early signs of infection can significantly reduce the transmission. Isolating individuals to prevent disease spread is also a key factor.

[Ezegbebe]

I completely agree with you, Adaeze. Properly cleaning equipment between patients is essential as it significantly reduces the risk of transmission. Cohorting patients with similar symptoms is also a key strategy to prevent unnecessary exposure and protect those who are more vulnerable. As healthcare professionals, even the most minor actions—like regular surface cleaning and consistent hand hygiene—can have a significant impact. It’s our responsibility to be diligent and uphold these practices to ensure the safety of both our patients and ourselves. Thank you for bringing attention to this important aspect of care.

[Oluwatosin]

I worked in a long-term facility, and the chain of transmission for an elderly resident with influenza is as follows:
• Infectious Agent:
Influenza virus
• Reservoirs:
An infected resident who may or may not be showing symptoms
• Portals of Exit:
Coughing or sneezing, which releases respiratory droplets from the mouth or nose
• Modes of Transmission:
Droplet transmission when the resident coughs or sneezes nearby
Indirect contact from contaminated hands touching shared surfaces like bed rails or doorknobs
• Portals of Entry:
Mucous membranes of the nose, mouth, or eyes of another resident or staff member
Touching the face after contacting contaminated surfaces
• Susceptible Host:
Elderly residents with chronic conditions or weakened immune systems who have not received the annual flu vaccine.

[Adaeze]

I work in an Acute medicine unit. Most of the rooms are 4 patient bed rooms. When a new patient is transferred, they may have Hospital Acquired Infections (HAI), such as VRE, ESBL or MRSA. When equipment are shared with these patients such as vital machines without properly wiping before using, diseases may be transmitted especially in immune-compromised patients. This can also result in severe health complications.

Most times, the unit is always in VRE outbreak. If hand-washing is strictly done between patients at all times, transmitting organisms between patient care will be low.

[Yu]

Hi Adaeze,

You made a great point—sharing equipment without cleaning it properly can lead to infections spreading quickly, especially with frequent patient transfers. Following infection control practices such as using proper PPE, handwashing, and disinfecting tools between each use is essential. Thanks for sharing!

[Natieja]

Adaeze I agree as well , it is so important to clean equipment between patients as this is a big mode of transmission. It is also important that we are cohosting patient with like symptoms together to ensure that we are not exposing patients that do not need to be exposed. There are little small things that we as staff can due to definetly protect ourself and are patient and we have to do re due diligence in ensuring we are cleaning surface and preforming hand hygiene .

[Ping]

Hi Adaeze,
Thank you for emphasizing the importance of preventing hospital-acquired infections. I work in a long-term care facility, and I’ve noticed that it’s quite common for residents to be readmitted with MRSA infections following hospitalization. Treating MRSA in long-term care can be particularly challenging due to the population we serve—many residents have weakened immune systems and impaired liver or kidney function. Additionally, the use of shared washrooms and tubs can further increase the risk of transmission. For these reasons, it’s crucial to strictly follow infection prevention and control protocols across all healthcare settings to help prevent infections and protect our residents.

[Rhoda]

The following is a breakdown of the norovirus chain of transmission in the long-term care facility where I work:

The norovirus is the infectious agent that causes gastroenteritis, which manifests as diarrhea and vomiting.

Reservoir: Infected staff members or residents who may harbour the infection even in the absence of symptoms.

Portals of Exit: The virus is released into the environment through vomiting and diarrhea.

transfer modes include direct contact with infected surfaces or fecal-oral transfer via contaminated food, water, or surfaces.

Portals of Entry: Oral mucosa, especially when the mouth or face is touched by hands infected with the virus.

Elderly inhabitants who have compromised immune systems and are more vulnerable to serious problems are considered susceptible hosts.

It is crucial for us nurses to adhere to appropriate infection control procedures in order to prevent the spread of the infections.

[Gagandeep]

At the care home where I used to work, we had a situation where one of the residents got the flu. She had a cough and a runny nose, and the virus came out when she sneezed or coughed. She touched the handrails and tables, and the staff didn’t realize she was sick yet. Another resident used the same handrail and then touched her nose without washing her hands. A few days later, she also started showing flu symptoms. Since many residents have weaker immune systems, it spread quickly to a few others before we could stop it. This shows how easily the flu can spread in a care home if we don’t catch it early and follow infection control steps like handwashing, cleaning surfaces, and wearing masks when needed.

[Pushpinder]

Hi Gagandeep,

I think this is a very good observation. I think that it is very important to ensure that all staff members, visitors and other residents are always performing good hand hygiene and following all protocols at the hospital or long term care/retirement homes that you work in. Following these guidelines and procedures are important because they can help prevent wide spread of viruses and other infections before it is too late.

[Natieja]

I work in long term care and the most popular I’ve seen over the past 10 years is the respiratory outbreaks.
Infectious Agent: Infkunza

Reservoirs: Patients/. residents, Staff members, family members, visitors

Portals of Exit: coughing, sneezing, talking, breathing, droplet

Modes of Transmission: there are many modes of transmission , through the use of equipments, through contaminated surfaces. Droplet, contact , improper IPAC practices

Portals of Entry: droplet, indirect contact, inhalation, improper Hand hygiene, wounds

Susceptible Host:residents, Staff members, family members, visitors, weaken immune system acute/ chronic disease

[Nnwuli]

I completely agree with you working in long-term care, respiratory outbreaks have definitely been the most common in my experience as well, especially during flu season or times when COVID-19 was more active.

Your breakdown of the chain of infection is spot on. I have seen firsthand how easily viruses like influenza can spread through something as simple as a shared blood pressure cuff or not properly disinfected surfaces. I also appreciate that you included family members and visitors as both reservoirs and susceptible hosts we often focus just on residents and staff, but visitors can play a big role in transmission too.

It really highlights the importance of consistent IPAC practices, good hand hygiene, and early identification of symptoms. One thing we’ve been doing more recently is reinforcing staff education on proper PPE use and encouraging sick staff to stay home, which has helped reduce spread in our facility.

[Anna]

Respiratory outbreaks are a persistent issue in long-term care, and Influenza follows a familiar pattern. The outlined chain of infection—from reservoirs to transmission methods—illustrates how easily it spreads. Factors like poor hygiene, contaminated surfaces, and improper infection control put vulnerable residents at greater risk. Preventing outbreaks requires a strong focus on infection control, including vaccinations, sanitation, and better hygiene practices among staff and visitors.

[Ping]

I work at a long-term care facility, and this past winter, we experienced several influenza outbreaks. According to the chain of transmission, the six links are the following:
The Infectious Agent: the influenza virus
The reservoir: an infectious resident, staff, or a visitor
Portals of Exit: coughing, sneezing, and talking
Modes of Transmission: droplet
Portals of Entry: mucus membranes such as mouth, nose, and eyes
Susceptible Host: vulnerable and immune-compromised resident and staff.

[Janecia]

Hello Ping,

I can concur with you as well. At my place of employment, we experienced recurring influenza outbreaks on a weekly basis over the winter months. However, with the consistent use of personal protective equipment (PPE), the numbers plummeted.

[Samoya]

Hello Ping.
Thank you for sharing your example of the chain of infection for influenza in the long-term care setting. I found it very relevant, especially given how easily influenza can spread in congregate environments like LTC homes and hospitals.
I currently work in a hospital on a complex rehab unit, and similar to your setting, we are especially cautious during flu season. In our unit, infection prevention and control (IPAC) practices are heightened during the winter months when influenza cases rise. As part of our preventative measures, we administer the influenza vaccine to patients with their informed consent. The hospital also offers and strongly encourages flu vaccination for all staff, which is a key component in breaking the chain of transmission.
Understanding the infectious agent, reservoir, portal of exit, mechanism of transmission, portal of entry, and vulnerable host is essential for determining the appropriate locations for interventions. Vaccination, for instance, can limit the portal of exit and transmission by lowering the number of susceptible hosts and the quantity of virus that infected individuals shed (Mostaghimi et al., 2021). In our unit, we use risk assessment to decide on the need for droplet/contact precautions, PPE use, isolation, or testing: as soon as patients start to have respiratory symptoms. Being proactive in identifying and responding to potential influenza cases helps prevent outbreaks and protects both patients and staff: many of whom may be immunocompromised or recovering from serious illness.

Reference
Mostaghimi, D., Valdez, C. N., Larson, H. T., Kalinich, C. C., & Iwasaki, A. (2022). Prevention of host-to-host transmission by SARS-CoV-2 vaccines. The Lancet Infectious Diseases, 22(2), e52–e58. https://doi.org/10.1016/S1473-3099(21)00472-2

[Janecia]

In many healthcare setting especially long-term care homes, the common cold or Rhinovirus has been notably widespread.
Infectious Agent: Rhinovirus
Reservoirs:Infected resident or staff or visitor
Portals of Exit: Respiratory tract eg. coughing, sneezing
Modes of Transmission: Droplet transmission through airborne, direct contact eg, touching surface after wiping/touching your nose or mouth.
Portals of Entry: Respiratory tract
Susceptible Host: a resident or staff or visitor who is not immune to the virus

[Pushpinder]

I work in a long term care health facility and I had a case where a resident was in isolation for norovirus.
Infectious agent: Norovirus
Reservoirs: Infected host could have been a guest who visited or could have occurred when resident attended an outing.
Portals of exit: Respiratory [sneezing or coughing]
Modes of Transmission: Droplet precautions are needed to prevent spread [could be airborne from sneezing or coughing and not wearing proper PPE or from touching surfaces without proper hand hygiene.
Portals of entry: Through the nose, eyes or mouth – enters respiratory tract.
Susceptible host: Residents or staff members who encounter the resident who are not vaccinated or immune.

[Ezegbebe]

Infectious Agent:
Methicillin-resistant Staphylococcus aureus (MRSA) – a type of bacteria resistant to several antibiotics.

Reservoirs:
An infected surgical wound of a post-operative patient.

Portals of Exit:
Drainage or discharge from the infected wound.

Modes of Transmission:
Direct contact – healthcare worker’s hands not properly cleaned after dressing the wound.
Indirect contact – contaminated bed linens, wound care supplies, or equipment.

Portals of Entry:
Broken skin or mucous membranes of another patient, such as through an IV site or a surgical incision.

Susceptible Host:
A post-operative patient with a compromised immune system or an open surgical wound.

[Ezegbebe]

Thanks for sharing this example—it does a great job of showing how influenza can spread so easily in a long-term care environment. It emphasizes how important it is to manage each step in the chain of transmission. Since many residents have weakened immune systems, it’s crucial to stay on top of infection control practices like hand hygiene, using droplet precautions, and promoting vaccination. Your example is a great reminder of why continued staff awareness and prevention efforts are so important in keeping everyone safe.

[Ezegbebe]

Thanks for sharing this example, Ping—it shows how influenza can spread so easily in a long-term care environment. It emphasizes how important it is to manage each step in the chain of transmission. Since many residents have weakened immune systems, staying on top of infection control practices like hand hygiene, using droplet precautions, and promoting vaccination is crucial. Your example is a great reminder of why continued staff awareness and prevention efforts are so important in keeping everyone safe.

[Nnwuli]

In my current role working in a long-term care facility, we had an experience with an influenza outbreak that clearly illustrated the chain of infection.

Infectious agent: The influenza virus.

Reservoir: One of our staff members came to work while unknowingly carrying the virus.

Portal of exit: The virus exited through respiratory droplets when the staff member was coughing and speaking around residents.

Mode of transmission: The virus was transmitted through droplets in the air and also through indirect contact when surfaces like doorknobs and handrails weren’t cleaned quickly enough.

Portal of entry: It entered other residents through their nose or mouth—especially those who were in close contact or required assistance with feeding or hygiene.

Susceptible host: Many of our elderly residents were highly vulnerable due to chronic conditions like diabetes, COPD, and weakened immune systems.

After identifying the outbreak, we quickly implemented infection control measures: isolation precautions, enhanced cleaning, and ensuring all staff wore masks and practiced hand hygiene consistently. We also reviewed our sick policy with staff to prevent similar situations in the future.

[Bunmi]

Thank you for sharing such a clear and practical example—it’s a powerful reminder of how quickly an outbreak like influenza can spread in a long-term care setting, especially when one link in the chain is overlooked.
Your experience highlights how crucial early identification and a rapid response are in minimizing the impact of an outbreak. The measures your team took—like implementing isolation, reinforcing hand hygiene, and reviewing sick policies—are exactly what’s needed to break the chain of transmission and protect residents.
It’s also a great example of how important it is to create a culture where staff feel supported to stay home when unwell, which can sometimes be overlooked in busy care environments. Your reflection not only shows strong infection control practices but also a proactive approach to preventing future outbreaks. Thanks again for the thoughtful insight!

[Bunmi]

In the Long Term Care Home where I worked, there was a newly admitted resident from the hospital who had C. difficile
Infectious Agent:
Clostridium difficile (C. difficile) – a bacterium that causes severe diarrhea and colitis.
Reservoirs:
A resident who has been on antibiotics and has developed a C. difficile infection. The bacteria are present in their feces.
Portals of Exit:
The resident’s stool, especially during episodes of diarrhea.
Modes of Transmission:
Indirect contact – staff who do not perform proper hand hygiene or fail to wear gloves while cleaning the resident or handling soiled linens/surfaces can carry the bacteria on their hands or clothing.
Portals of Entry:
Another resident’s mouth or mucous membranes (e.g., touching their mouth after contact with contaminated surfaces or hands of a healthcare worker).
Susceptible Host:
Another elderly resident with a weakened immune system, chronic illness, or who is currently taking antibiotics.
This outbreak highlights how easily infections can spread in LTC settings, especially when residents are vulnerable and staff are managing multiple care tasks. It reinforces the importance of proper hand hygiene, environmental cleaning, PPE use, and communication among healthcare team members to break the chain of transmission.

[Samoya]

I work in the hospital and a common healthcare-associated infection seen is Methicillin-resistant Staphylococcus (MRSA).

Infectious agent: Staphylococcus aureus (MRSA- a drug resistant strain)
Reservoir: Infected or colonized patients (wounds, nares), healthcare workers’ skin, or contaminated hospital equipment
Portal of Exit: Wound drainage, nasal secretions or skin cells from an infected or colonized person
Mode of transmission: Direct contact- through hands of health care workers or contaminated equipment
Portal of Entry: Broken skin (Surgical incisions, IV sites, wounds), mucous membranes
Susceptible host: postsurgical patients, patients with open wounds, elderly patients and immunocompromised individuals.

[Yiqun]

I am working in a long term care facility and the most common issue in the LTC is respiration infection such as Flu, COVID or RSV, especially during winter season. Due to residents enjoyed to attend group activities or having meal in dinning room, it is crucial for nurse to identify sign and symptoms of the disease and take action accordingly.

Infectious Agent: virus

Reservoirs: common area, sicked person

Portals of Exit: sneezing, coughing, sharing utensils/food

Modes of Transmission: droplets, airborne

Portals of Entry: respiratory tract

Susceptible Host: elderly, immunocompromised s.

[Anna]

Hello, my name is Anna. I work in step-down ICU. Lately, we have been seeing a lot of patient with influenza A virus.

Infectious Agent: Influenza A virus.
Reservoirs:Infected patients, healthcare workers, or visitors.
Portals of Exit:Respiratory droplets from coughing, sneezing, or talking.
Modes of Transmission: Droplet transmission or contact with contaminated surfaces.
Portals of Entry: Nose, mouth, or eyes.
Susceptible Host: Elderly patients or those with weakened immune systems.

[Jazmin Guadalupe]

During one of my placements, I observed some healthcare staff using nails polish and jewelry while providing patient care. Hand and wrist jewelry can interfere with handwashing and create areas where microorganisms can accumulate. During pericare, E. coli bacteria can be spread through feces. It is important to maintain a high level of cleanliness and hygiene to prevent infections. Wearing jewelry and nail polish can make it more difficult to maintain this degree of hygiene and increase the risk of introducing pathogens.

Infectious Agent: E. coli bacteria
Reservoir: infected patients, health care workers, visitors,
Portal of Exit: fecal, excreted in the feces of humans or animals
Mode of Transmission: fecal-oral route, contaminated food or water, direct contact, cross-contamination
Portal of Entry: bacteria enter the body through the mouth, often through contaminated food or water, or by touching contaminated surfaces and then touching the mouth.
Susceptible Host: Infants, young children, elderly residents, and persons with an immune system are at higher risk.

[Semhar]

The train of transmission is a concept used in epidemiology to describe how infections spread from one host to another. It highlights the various components that must be present for an infection to occur. In long-term care homes where I work, we had an influenza outbreak during the Winter season. The pathogen is the influenza virus. The reservoir is infected humans. The portal of exit is when the virus exits the infected host through respiratory secretion when an infected person coughs, sneezes, or talks. The mode of transmission is that the virus can spread directly when a person inhales droplets expelled by an infected person. The virus can also be spread indirectly by contaminating surfaces that others may touch. The portal of entry is when the virus enters a new host through the mucous membrane of the nose, mouth, or eyes. A susceptible host is a person who has not been vaccinated against influenza or who has a weakened immune system.

[Author]

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