The CMD pandemic was a pandemic of Cariappa-Muren disease (CMD) caused by piscine transmissible amyloidotic encephalopathy (PTAE). It was spread through farmed tuna contaminated with PTAE between 2034 and 2040. The number of confirmed infections stands at
1,620,639 (with a death toll of 39,715) as more cases continue to be appreciated because of CMD’s long incubation period.
The World Health Organisation (WHO) has determined that the feeding practices of Lassgard Bioteknik, the company that developed the contaminated tuna, were the likely origin of the PTAE epizootic that led to the CMD pandemic, though this remains a controversial matter of debate amongst a minority of researchers.
Aggravated by a misinformation campaign and China’s initial censorship of CMD, the CMD pandemic resulted in severe social and economic disruption, and is seen as directly responsible for the establishment of G6 in 2041.
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The majority of researchers agrees that the pandemic of Cariappa-Muren disease (CMD) resulted from an epizootic of piscine transmissible amyloidotic encephalopathy (PTAE) in Lassgard tuna, which was introduced to the food chain in 2034 and went undiscovered until 2039. With Lassgard tuna accounting for roughly 80% of worldwide tuna consumption by 2039, it is considered to be the primary infection vector of the CMD pandemic. The increased use of implantable multielectrode arrays (MEAs) is also seen as a contributing factor, as PTAE prions are resistant to conventional chemical and physical decontamination methods, and can be transmitted through reusable neurosurgical equipment.
The first victims of the PTAE-infected tuna were domestic cats who became symptomatic much quicker due to their lower body mass and brain weight.  In November 2038, Sunil Cariappa found a notable uptick in cat mortalities through the Global Public Health Intelligence Network (GPHIN). He requested necropsies on several of the deceased cats and found that many exhibited signs of what appeared to be feline spongiform encephalopathy (FSE), though the lack of any apparent spongiosis in the brain tissue prevented him from confirming this diagnosis. When he found the common link between all FSE-affected cats to be their diet, which included Lassgard tuna, he surmised that this line of tuna was infected with a novel prion agent.
Worried that the prion infection was spreading to humans as well, Cariappa reached out to Connie Muren, whose team at the University of Düsseldorf had published an article on WedgeWoo, a patient of atypical variant Creutzfeldt-Jakob disease (vCJD) in Tokyo, Japan. Since WedgeWoo’s young age fell well outside established incubation periods and no vCJD-specific treatments had any effect, Muren had proposed that a new sporadic prion mutation was the causative agent.  Having been alerted to her article because it also mentioned a lack of spongiosis, Cariappa suggested to Muren that WedgeWoo had instead contracted the same prion agent responsible for the outbreak in cats. A subsequent analysis of WedgeWoo’s dietary habits revealed a 2034 livestream sponsored by Lassgard Bioteknik, during which WedgeWoo consumed large amounts of sushi made with Lassgard tuna. WedgeWoo, who died on November 29th 2038, has posthumously become known as the index case of CMD.
In December 2038, Cariappa joined Muren’s team in Düsseldorf to confirm their find. They analysed brain samples of preprocessed Lassgard tuna sold in East Asia, Europe, Africa, and the United States (US), finding that a significant proportion of the samples displayed characteristics of amyloidosis, such as numerous plaque deposits that resembled PrPSc aggregates. They described this amyloidosis as PTAE, though there was some uncertainty regarding its origin. At the time, the most likely candidate was considered to be an inherited prion mutation attributed to Lassgard Bioteknik’s practice of genetically modifying its fish stock.
The team reported its discovery to the Global Foodborne Infections Network (GFN) in January 2039, but with only a single suspected case in humans at that point, no immediate health hazard to the population was considered. The only concession was a notice issued in the monthly Bulletin of the World Health Organisation (WHO) to advise against feeding tuna to pets. Muren believed that the WHO was underestimating the long-term implications of PTAE’s discovery and publicly critiqued the organisation’s inaction, which prompted GFN officials to convene an Outbreak Control Team (OCT) in February 2039. Muren decided to focus the OCT’s efforts on determining PTAE’s transmission potential to humans while Cariappa developed several epidemiological models.
Passage of infected brain material collected from Lassgard tuna to transgenic mice revealed that they could develop a clinical disease consistent with the pathology described in WedgeWoo’s case. By the time this test was completed in July 2039, five more suspected human cases had been detected in Japan, all showing similar symptoms and dietary habits. When the OCT reported its additional findings to the WHO, the decision was made to formally declare a Public Health Emergency of International Concern (PHEIC) on July 20th 2039 and allocate more resources to the OCT. 
Although public awareness of prion diseases and their years-long incubation periods had increased with the second wave of vCJD cases in the United Kingdom and Europe, the WHO faced difficulty in convincing authorities that the discovery of CMD represented a public health threat.  This has been attributed largely to the perceived lack of immediacy when compared to other foodborne disease outbreaks, in that significant fatality rates would only gradually become apparent in the coming decades. In addition, the WHO was met with pressure from Lassgard Bioteknik, which refused to reveal any details about its closely guarded production process, and the Aquaculture Advisory Council (AAC), which lobbied heavily against any efforts to halt the sale of Lassgard tuna pending the investigation.
These hurdles continued until October 2039, when a leak of internal Lassgard Bioteknik correspondence reflected that president and chief executive officer (CEO) William Lassgard had been aware as early as March 2037 that the company’s tuna stock was exhibiting erratic behaviour due to the PTAE epizootic. The leak and the resulting scandal turned public opinion against Lassgard Bioteknik and allowed the WHO to successfully ban the sale of Lassgard tuna. The WHO elected to classify the outbreak of CMD as a pandemic despite its low contagion level, arguing that CMD had managed to spread to multiple continents in the years it went undiscovered. In coordination with the Global Outbreak Alert and Response Network (GOARN), the WHO issued a global alert on October 25th 2039.
When the WHO declared a PHEIC in July 2039, the Chinese Communist Party (CCP) began to censor all CMD-related news in China, blocking access to foreign data through the Great Firewall and declining any cooperation with the WHO.  As CMD became more prominent in international media and Lassgard Bioteknik intensified its misinformation campaign, Chinese citizens gradually became aware of distorted facts about CMD, leading to rumours that “an exceedingly dangerous pathogen had been spreading unchecked for years.” The lack of immediate fatalities due to CMD’s long incubation period created the impression that the CCP was “covering up thousands of deaths,” and that China was “walled off from a world that had descended into chaos.” 
On January 25th 2040, then-CCP General Secretary Chen Baoqiang warned that China was facing “a grave situation” and held a Politburo meeting to discuss a response to the CMD pandemic.  In February 2040, the CCP opened talks with the WHO for the adoption of its contact tracing strategy, and for its investigators to assess the CMD pandemic in mainland China. The resulting negotiations were fraught, with the CCP refusing to deploy the diagnostic colloids supplied by Zhupao in favour of Huawei‘s design for implantable multielectrode arrays (MEAs). In lieu of an investigative team, the CCP asked for then-WHO Director-General Yang Jinglei and Muren to visit China, with Cariappa taking Muren’s place following her disappearance on March 4th 2040.
Following accusations that the CCP was misrepresenting the purpose of Cariappa’s presence in China, Xu Shaoyong invited him and Li Qiao Fan to Zhupao’s headquarters in Shanghai in April 2040, and accused the CCP of using the CMD pandemic as an excuse to “turn temporary health measures into permanent fixtures of the surveillance state.”  On April 12th 2040, the CCP authorised the National Health Commission (NHC) to cooperate fully with Cariappa and the WHO. After the OCT issued its official report to the NHC, Yang declared the CMD pandemic contained on April 19th 2040.
Accounting for 90% of all tuna consumption by 2039, China and Japan were identified as the epicentres of the CMD pandemic, though Sweden is considered to be the location of its origin. Based on product tracking data of Lassgard tuna and CMD-specific susceptibility rates, the WHO estimated that approximately three million people were infected with CMD during the five years Lassgard tuna was sold for human consumption. A more defined estimate was complicated by lingering issues with enforcing the ban of Lassgard tuna. Not all vendors with surplus stock immediately complied with the ban, leading to contaminated tuna still being sold until full compensation was offered in late 2040. Lassgard tuna was also available on the illicit market until well into 2041.
After the global alert was issued in October 2039, the WHO coordinated with Zhupao and local, regional, and national health agencies to distribute information packets and diagnostic colloids with CMD-specific sensors to physicians and hospitals, with all positive diagnoses logged by GOARN. Continued G6 monitoring has tallied the number of confirmed CMD infections up to a current total of
1,620,583. The yearly incidence rate has steadily tapered off since 2047, but extrapolated epidemiological models from the bovine spongiform encephalopathy (BSE) epidemics indicate that a second wave of CMD cases in individuals with a specific genotype is likely to be observed in the coming decades.
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- Cariappa, S; Muren, C. (July 2039). “Acquired Prionopathic Neurodegeneration Syndrome (APNS): Pathology, Transmission, and Epidemiology.” Bulletin of the World Health Organisation. ↩
- Muren, C. (February 2023). “Overall incidence of variant Creutzfeldt-Jakob disease expected to double after second wave of cases.” News Medical. ↩
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