Case scenario: In Macondo (a hypothetical tropical country with presence of Aedes mosquitoes in most...

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Case scenario: In Macondo (a hypothetical tropical country with presence of Aedes mosquitoes in most of its urban areas), clusters of cases of acute exanthematous illness have been reported from various areas since late 2019, and, in May 2020, Zika virus (ZIKV) was identified as the aetiologic agent. In June 2020, the local Ministry of Health recognized circulation of ZIKV in Macondo. Aracataca is the largest city in Macondo, followed by the city of La Mancha. The Epidemiologic Surveillance Office (ESO) was first alerted to cases of an acute exanthematous illness early in 2019. Reporting of cases increased during March and, in April, the ESO established 10 public emergency health centers in ‘La Mancha’ as sentinel units for systematic surveillance of patients with acute exanthematous illness of unknown cause. These sentinel units were strategically chosen in order to identify cases across all 12 public health districts of La Mancha. The units searched retrospectively for suspected cases by review of medical charts of patients treated since February 15, continued with prospective case detection, and submitted weekly reports of identified cases to the ESO. During February 15−June 25, a total of 14,835 cases of an indeterminate acute exanthematous illness were reported from the 10 sentinel units in ‘La Mancha’. The overall attack rate was 5.5 cases/1,000 persons (4.6 cases/1,000 men and 6.3 cases/1,000 women, 8.2 cases/1,000 children 40 years of age). Epidemic curve: The peak of the epidemic curve occurred in the first week of May. This was 1 week after the molecular diagnosis of ZIKV in 8 patients living approximately 50 km outside of La Mancha. There was intense media coverage of the outbreak at the time of the peak.  2 of 3 Reporting of suspected dengue cases in ‘La Mancha’ did not vary substantially from that in other years 2,630 cases were reported, of which 1,187 cases (45.1%) were positive for dengue IgM, 90 cases (3.4%) were positive for dengue virus (DENV) nonstructural protein 1 (MS 1), and 240 cases (9.1%) were positive for DENV by reverse transcription PCR. During the same period, 58 cases of suspected chikungunya (CHIKV) were reported and 24 patients with suspected Guillain-Barré syndrome were hospitalized. The median age of case-patients was 26 years (interquartile range 11–39 years), but all age groups were affected, which is a pattern typical of spread of new microorganisms in a susceptible population. Median duration of symptoms at time of medical attention was 1 day (interquartile range 0–3 days). All patients had exanthema and most 90.2% had pruritus. Fever (35.1%), arthralgia (26.5%), headache (25.6%), and myalgia (21.6%) were less common. Identification of ZIKV, CHIKV and DENV as aetiologic agents of acute exanthematous illness suggests that these three Aedes mosquito−transmitted viruses were co-circulating in ‘La Mancha’ and highlights the challenge in clinically differentiating these infections during outbreaks. Laboratory-confirmed cases of infection with ZIKV were simultaneously identified in other cities within metropolitan ‘La Mancha’ and in other states of Macondo. Task: You are the person in charge of communicable disease control in ‘Aracataca’ the largest city of Macondo and when checking your surveillance system there is an increased number of reports of an exanthematous illness similar to the one in ‘La Mancha’. Your task is to prepare a proposal for your outbreak investigation in Aracataca, to present to the Macondo Ministry of Health. It will need to address the 10 steps of outbreak investigation, your recommendations for interventions, and conclusions about your proposed plan. *NOTE: There is no data available to perform specific descriptive epidemiology; however it is important for you to describe what you might ideally like to do, if you had data available* 1. Prepare to investigate 2. Verify the diagnosis and confirm the existence of an outbreak: Differential diagnosis 3. Construct a working case definition 4. Find cases systematically and record information: hint! how are you going to do it and which information would you like to collect and why? Based on what is currently known about ZIKV 5. Perform descriptive epidemiology* 6. Generate hypotheses and re-evaluate hypotheses epidemiologically 7. Compare and reconcile with laboratory and/or environmental studies 8. Implement control and prevention measures: Check all the possible complications of ZIKV infections and plan your control and preventive measures accordingly. Hint! It goes beyond than vector control.  3 of 3 9. Initiate or maintain surveillance 10. Communicate findings

Sunabh · Accepted Answer

Running Head: COMMUNICABLE DISEASE CONTROL	1
COMMUNICABLE DISEASE CONTROL		2
ASSESSMENT 2:
TM5525: COMMUNICABLE DISEASE CONTROL
Table of Contents
Introduction	3
1. Outbreak Investigation	3
2. Verifying the Diagnosis and Confirming the Existence of an Outbreak: Differential Diagnosis	4
3. Constructing a Working Case Definition	5
4. Finding Cases Systematically and Recording Information	5
5. Performing Descriptive Epidemiology	6
6. Generating Hypotheses and Re-evaluating Them Epidemiologically	6
7. Comparing and Reconciling with Laboratory and Environmental Studies	7
8. Implementing Control and Prevention Measures	8
9. Initiating or Maintaining the Surveillance	8
10. Communicating the Findings	9
Conclusion	9
References	10
Introduction
Outbreak investigation is a highly complex as well as time-consuming set of procedures, which are majorly used to identify the potential causes of the disease. It would be essential to understand that epidemic limited to a localised increase in the incidence of disease could be presented as outbreak. This paper would present the outbreak investigation for the presented case study of Macondo.
Further, efforts would be made to present an effective hypothesis along with effective control and prevention measures for control of outbreak. Moreover, this outbreak investigation will conclude with proposed methods of surveillance and communication of findings with public and department of disease control and local authorities of the city. 
1. Outbreak Investigation
There could be a number of factors, which could be presented as determining factors concerning the investigation of potential outbreak. This is majorly because of the fact that outbreak investigation requires extensive planning, severity of the presented illness, source of infection, number of cases, and mode of transmission along with availability of prevention and control measures. As suggested by Pessoa et al. (2016), it would be essential to understand that outbreak investigations are fostered by the health departments. When the number of infected individuals becomes large, the disease might be severe and when there is a need to identify potential control, measures in order to prevent the transmission to others unless prompt control measures.
Preparation for the investigation starts even before leaving for the fieldwork irrespective of the decision to conduct fieldwork. Preparation step can further be divided into major categories that are, a) scientific or investigative issues, and b) operational and management issues. The latter is an essential step during preparation because a team rather than a single individual conduct most of the investigations. Therefore, the selection of team members would be crucial while planning for current investigation. Further, there would be need of an action plan, scientific supplies, equipment, or equivalent funds to arrange for the same.
Hill et al. (2018) mentioned and argued upon the fact that acquiring appropriate and exact knowledge of the geographical location and the outbreak would be essential along with scientific knowledge of the disease. Moreover, planning for current outbreak investigation would also require special protective equipment such as downs, gloves, masks, repellents and much more in order to prevent the team from infection. 
2. Verifying the Diagnosis and Confirming the Existence of an Outbreak: Differential Diagnosis
	It would be essential to understand that the investigators would be required to identify the expected number that is, the number of infected individuals from previous month of weeks in order to establish a comparable period during previous few years. Further, the excess number of cases from expected number does not indicate the existence of outbreak. Therefore, other factors would require analysis such as, seasonal variation, notification variation, diagnostic variation and change in population size along with the consideration of false epidemic or diagnostic mistake (Waddell & Greig, 2016). 
	Kurup, John, Ponnaiah and George (2019) mentioned that diagnosis verification is quite similar to verification of the existence of outbreak and is required to rule out the false diagnosis and to ensure proper identification of a disease. Investigation team would be required to talk with health workers along with reviewing presented clinical findings and laboratory results. This is majorly because talking with the patients would allow the investigation team to have a better understanding of clinical features of the outbreak. Likewise, summarising the clinical findings along with frequency distribution would help in the confirmation concerning existence of a disease.
3. Constructing a Working Case Definition
A case definition is prepared usually for the identification of infected cases during an outbreak. In other words, a case definition is simply a criterion, which could be used to decide whether an individual should be classified as infected with the disease of interest. Therefore,

Case scenario: In Macondo (a hypothetical tropical country with presence of Aedes mosquitoes in most of its urban areas), clusters of cases of acute exanthematous illness have been reported from...

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