Rabies Outbreak: Causes, Transmission, and CDC Investigation

Since the 1900s, rabies mortality in the United States has decreased from approximately 100 fatalities annually to about one or two (World Health Organization [WHO], 2017).

Suppose is mainly due to the routine vaccination of domestic animals. Also, the majority of the population in the United States has easy access to health care, and post-exposure prophylaxis is readily available (CDC, 2011). The United States population is also well aware. It has access to a variety of resources that would allow them to research the risks of being bitten by an animal, especially a wild animal such as a bat, raccoon, bat, skunk, fox, coyote, and domestic pets as well.

These are all things that may not be as accessible to the rest of the world, which is a likely reason why most deaths due to rabies occur in areas with less than adequate health care in combination with living in an area that does not vaccinate domestic animals and has no access to the internet or other resources to keep educated on a topic unless provided to them.

Global Rabies Statistics and Healthcare Access

This limitation of awareness found in Thailand, where although knowledge about rabies and its severity is high, “awareness about bat transmission specifically was deficient.” Only 10% of the people who took a survey identified bats as a potential source of rabies, and 36% said they would likely not make any specific action if bitten by a bat (Robertson, Kis, Boonlert Lumlertdacha, et al., 2011). According to the WHO, although rabies affects all continents, 95% of deaths occur in Asia and Africa. Even if rabies post-exposure prophylaxis (PEP) is readily available to people in these areas, the costs of PEP are $40 and $49, respectively (WHO, 2017). A value that even some uninsured American citizens may have difficulty paying, let alone a person in Asia or Africa whose “average daily income can be between $1-2 per person” (WHO, 2017).

Furthermore, the diagnosis of rabies has also evolved.

Previously, the disease was a post-mortem diagnosis in animals, which means that the animal, if not dead already, had to be euthanized to take brain samples and confirm the diagnosis (CDC, 2011). Today, instead of euthanizing a perfectly healthy animal, the animal can bewatched for ten days after it bites someone. If no symptoms of rabies appear, it means the animal is rabies-free (CDC, 2011). That only decreases harm to healthy animals but also reduces the need to treat prophylactically, which, according to the WHO, is high, “typically exceeding 3,000” (WHO, 2017). Diagnosing rabies in humans is quite different, and although there are many diagnostic tests available, the WHO reports that those available are not “suitable for detecting rabies infection before the onset of clinical disease.”

Fatal Infestations

The “Fatal Infestations,” a video about the rabies outbreak, was devastating, mainly because rabies is a preventable and curable disease if caught before symptoms of the infection emerge.

Since rabies is an infection of the nervous system, symptoms include seizures, erratic behavior and aggression, excessive salivation (drooling), aversion to water (hydrophobia), and even paralysis and coma. Once any of these symptoms manifest, the disease is too far gone, and recovery is unlikely (CDC, 2011). Although physicians likely know the symptoms of rabies well, they often miss the diagnosis. In the medical field, there is a common saying, “If you don’t think of it, you will not diagnose it,” and in this case, rabies was not thought of as a possibility, just as the video proposed.

An epidemiological investigation requires specific steps to take in whichever order the investigator deems necessary (Gregg, Michael B, 3-13).

The video shown in class showed a small portion of what an actual investigation entails. The investigation began when local health departments called the CDC because of concerns of an outbreak. The video shows the CDC arriving and speaking with the families, acquiring what is called descriptive epidemiology: when, where, who, how many (Gregg, Michael B, 156-157). They looked for connections between all three victims now in a coma, intubated, and in the ICU. They then conducted a series of lab tests and imaging on all patients to diagnose the cause, but they did not succeed in making a diagnosis.

When the first fatality occurred, and the organ donor was identified as the source, descriptive epidemiology continued, now centered on the donor himself.

The CDC went to the patient’s home and spoke to friends and family. Luckily, this led to information about a bat bite on the donor’s chest in the previous weeks. The CDC then requested an autopsy and sent investigators to the donor’s home looking for the bats with infrared lenses. Multiple bats were found and taken to the CDC, where they were tested for the rabies virus. They found the same rabies virus in both the donor and the bat, and the source of the infection was found (“Fatal Infestations”). The video ends with the death of the last living victim.

In any situation where an individual is still alive and on the brink of death due to an unknown cause, which has already killed others, the involvement of local health departments and the CDC is crucial to determine the cause and source to treat and prevent further spread. Any initial investigation requires a case count and case definition (Gregg, Michael B., 157). In this situation, the case definition would have been: erratic behavior, seizures, and coma. The count would have been three with the first victim as patient zero. The video revealed that the symptoms began approximately 3 -7 days after the organ transplant surgery, meaning that whatever the cause, its symptoms occur rapidly andhave catastrophic effects. This would add pressure on me as an investigator to conduct my work not only accurately, but also very quickly (Gregg, Michael B, 10-13). My next step would be to begin data collection.

Descriptive epidemiology

Descriptive epidemiology: Demographics, exposures, similarities between all three cases, hospital information, and discussions with the doctors to determine if the infection was from the surgical room, the tools used, the staff present, etc. Since it is unknown whether or not any of these things are the source, I would be concerned about a larger range of exposure and a possible epidemic.

This information helps form a hypothesis of the possible source of infection and diagnosis; it would also help me decide whether or not to launch a full investigation (Gregg, Michael B, 186). In this case, I would because of the high risk of an epidemic of an unknown disease that can kill within 3-7 days. Once I ruled out the organ recipient hospital as the source of infection, I shifted my hypothesis to the donor hospital and the donor himself as the possible sources.

I would use visual aids and maps to help graph the case count, orient them in place (Gregg, Michael B, 191-196). It will help as I gather information from the donor hospital. Doing this may show the point of origin of infection and narrow down the possible source. This shows that as investigators progress through the investigation, they will also change and narrow the hypothesis until they find the true source.

Key Information Required About the Donor

The information I would require about the donor includes: symptoms of the donor on arrival to the hospital, which included: erratic behavior, seizures, and drooling. Information gathered from friends and family on recent exposures, which would reveal the bat bite weeks back. The combination of the bat bite and the symptoms, the doctor in me, would immediately be concerned about rabies.

Just as the CDC did, I would request an immediate biopsy of the donor, looking specifically for Negri bodies in the brain (CDC, 2011), as well as send investigators to the home to look for bats. After confirmation of the diagnosis of rabies, no one can do much for the surviving victim who received an organ from the infected donor. Unfortunately, they were already presented with symptoms, and as mentioned previously, recovery is not likely.

Rabies is a viral disease which usually spreads to humans by contact with infected animals.

Now, although the video did not discuss what happened after the surviving victim passed away, it is important to know that any epidemiological investigation does not end there. It is imperative to continue assessing risks of exposure to other people besides the initial victims. Knowing that the latency between exposure to rabies and symptom manifestation of the disease is between 1 week and three months, it is essential to determine whether an exchange of bodily fluids between the donor and any family and friends occurred (CDC, 2011).

If the transmission of rabies is likely, they should administer PEP, especially if the patients have not presented with neurological symptoms, and in this way, they can prevent more casualties. Furthermore, I would be concerned about the presence of bats in the neighboring areas of the donors’ homes.

If his home had bats, it is also likely that there are bats in other homes, which would place their inhabitants at risk of acquiring rabies if bitten. A very important step in an epidemiological investigation is the formation of a written report outlining the findings and recommendations (Gregg, Michael B, 3-13, 73-76).

Educational Outreach and Preventive Measures

Even more important is the execution of the recommendations as well as the implementation of prevention measures to keep healthy people healthy and risk-free of the disease. This includes surveillance for bat, wild carnivore, and rabid dog sightings. Bats and rabid animals may infect other domestic animals, and therefore, there is a need to conduct surveillance of changes in domestic animal behavior.

I would thus release educational pamphlets to the population, alerting them of the possible risk of rabies if bitten by these animals and instructions on what to do if bitten, such as 1) Immediately spray with soap and water, as the saliva of the animal transmits the virus. 2) Make an appointment with their doctor and be evaluated for the possible risk of exposure and, if needed, receipt of PEP. To aid in reducing rabies-infected animals from the streets, I would ask for assistance from Animal Control to retrieve any raccoons, bats, and other possible reservoirs from the roads.

The above includes what I would do if I were the investigator on the rabies case.

As explained, I would do some things differently from what was seen in the video. Because of my medical background, I believe I may have been able to detect the possibility of rabies sooner and avoid the delay in diagnosis. I would have also used visual aids to help identify the common area of exposure and the pattern of transmission. Although in this situation, the investigation took place in the United States, certain risk factors were more important than others, such as bats versus domestic animals. If the research had taken place on an international level, there would no doubt be different obstacles to overcome, such as a language barrier, cultural differences, and political issues. These would cause significant delays in acquiring data and arriving at a diagnosis quickly.

Challenges in International Rabies Investigations

Moreover, certain places of the world do not trust the Western world, and this would affect the swift formation of the hypothesis by precluding data collection, as well as the creation of prevention and treatment plans to contain the infection. My focus, in an international setting, would be less on wild animals and more on domestic animals, which rarely get rabies vaccines and the most common causes of rabies outside of the United States (WHO, 2017). The plan would include vaccinating as many dogs as possible with the aid of veterinarians, both local and international, watching street dogs for signs of rabies, and putting them down if confirmed. They are teaching the population about ways to protect themselves and others. Inform families that those most at risk of acquiring rabies are their children (Finnegan, C. J., S. M. Brookes, et al., 2003).

Community Education and Prevention

It is essential to educate the population about all the likely reservoirs to avoid the issues mentioned earlier that Thailand faces. Preventing the re-emergence and epidemics of a disease is the goal. They implement prevention measures. Certainly, they will face challenges in supplying enough rabies vaccines for all the dogs, and they cannot prevent every risk of exposure. Another thing to consider is access to health care.

If a dog bites someone, do they know where to go to get PEP? Can they get there quickly and safely? Will it be affordable? Public health officials must address these obstacles, especially in international settings where limited access to healthcare makes arriving with a clear plan essential. Overall, the investigation conducted during the rabies video does show the typical course of an epidemiological investigation.

I do think there were some time delays in reporting the issue to the CDC and diagnosing the donor with rabies. But fortunately, the disease had only been transmitted to the three victims. It is important to keep people as well as practicing physicians informed about rabies, its hosts, transmission, treatment options, and prognosis.

Rabies Outbreak: Causes, Transmission, and CDC Investigation

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Since the 1900s, rabies mortality in the United States has decreased from approximately 100 fatalities annually to about one or two (World Health Organization [WHO], 2017).