China Bug – Is It Ebola-like Bird Flu?

CHINA's official Xinhua news agency confirmed this week earlier wire reports about the mysterious deaths of 27 farmers in several villages around the cities of Ziyang and Neijiang in Sichuan province.

Another 41 people in Sichuan have also fallen seriously ill.

All victims had been exposed to swine and developed high fever, fatigue, nausea, vomiting, and 'became comatose later with bruises under the skin', according to Xinhua. The provincial health authorities insist that 'the disease is absolutely not Sars, anthrax or bird flu'.

Instead, they ascribed the outbreak to a common swine bug called streptococcus suis. Based on information from the Chinese, the World Health Organisation (WHO) agrees that the symptoms 'seem consistent with' the diagnosis.

Could the WHO be wrong? Are the provincial authorities prevaricating?

But, first, what is this bug and why are these Sichuan cases less likely to be it? According to The Merck Veterinary Manual, this is a bacterium that lives in the noses, throats, guts and genitalia of pigs. Thus, farmers exposed to droplets of swine saliva, as well as slaughterhouse workers, butchers, and cooks who have open wounds who handle pork and pig innards could become infected.

Yet, despite its prevalence in pigs - up to 15 per cent of a herd could be carriers - human cases are rare as only one out of a total of 35 serotypes of the bacterium causes serious infections in people.

In humans, the bug invades the membranes covering the brain and spinal cord causing meningitis, with severe headaches, high fever, vomiting, confusion, stiff neck, loss of hearing and coma. There can also be bleeding from blood vessels beneath the skin, and the patient can go into toxic shock, with damage to the heart.

Sounds like the mysterious illness in Sichuan?

Note, however, that most cases have been reported in northern Europe and southern Asia, where intensive swine management practices are used, perhaps at least on the scale seen in the Pulau Bulan farm that supplies Singapore with about 6,500 pigs every week, according to the AVA. That does not sound like rural China.

Human cases have been seen in Singapore too, but they are very rare. In fact, until this Chinese claim, less than 150 human cases have been reported worldwide.

A total of 68 patients in Sichuan sounds unlikely for various other reasons too.

First, the bacterium is easily treated in pigs with penicillin. Though it can survive for long periods, it is also easily destroyed with soaps and dilute disinfectants.

Secondly, the high mortality also makes the cause somewhat less likely to be bacterial in origin, as bacterial infections are rarely as lethal.

Thirdly, the bug seems to spread between herds not only through the introduction of apparently healthy carrier pigs but also by flies, which can travel up to 2km between farms on their own. If flies got on to vehicles, they could go farther. Carcasses of dead pigs could also transport the bacteria.

But up to 75 villages are affected in Sichuan. These are clustered around 40 townships in different counties, which represent large geographical distances. This suggests the possibility of transmission by migratory birds.

Quite apart from the fear that pigs, which often carry the human flu virus, could contract bird flu and act as a 'blender' to speed up the process of its mutation, several facts suggest that the mysterious illness sounds a lot like influenza, some scientists believe.

Far-fetched?

In December 1979, the British Medical Journal published a letter from an army physician that had laid undiscovered in a trunk in Detroit for 60 years. In the 1918 letter, the doctor who was attending to soldiers in Boston during the devastating pandemic that year described in graphic detail how they were dying from the flu: 'Two hours after admission they have the mahogany spots over the cheek bones and a few hours later you can begin to see the cyanosis extending from the ears and spreading all over the face, until it is hard to distinguish the colored man from the white.

'It is only a matter of a few hours then until death comes and it is simply a struggle for air until they suffocate.' (Cyanosis is a bluish or purplish tinge to the skin.)

Note that reports described the Sichuan patients as having skin that turned very dark. Some H5N1 bird flu variants can produce bleeding under the skin. The index case in Thailand's human cases of bird flu this year was initially misdiagnosed as dengue hemorrhagic fever because of that bleeding.

What about the meningitis seen in Sichuan?

The H5N1, in fact, already has genes that can attack the brain. According to recent papers in Virology and The Journal Of Virology separately, this ability is seen in H5N1 samples isolated in 2001 and 2002 from poultry and birds in Hong Kong, and from a bird flu patient who died in the ex-colony in February 2003. Thus, it is very possible for any H5N1 circulating in mainland China to have this (neurotropic) characteristic.

Supposing it was bird flu in Sichuan, where could it have come from?

Probably from Qinghai province, just north-west of Sichuan. There, a major outbreak of bird flu occurred in April at a nature reserve, where 8,000 birds across five species - and also some mammals - died. Only in May would the Chinese authorities own up to it.

Now the weather has turned cold early at Qinghai, so birds there may have already started migrating out. Indeed, in June, China reported two outbreaks in birds at Tacheng city in Xinjiang province, which lies northwest of Qinghai. This week, there were wire reports about outbreaks in the Primorie and Chany Lake reserves in Russia, where more than 500 birds have died.

Here is the cause for concern.

When it first happened in Qinghai, an Internet daily called Boxun.com reported the outbreak, which the authorities denied. Human cases and fatalities, involving six tourists and 121 locals, were also detailed. Then, 17 of 19 Boxun reporters involved were jailed.

In May, China reported to the international authorities that there had indeed been an outbreak among birds in Qinghai but denied any human cases. Yet, it effectively hindered the WHO authorities from investigating the outbreak. Indeed, the 1.3 billion strong nation has never reported any human cases of bird flu that, since 2003, has killed at least 57 people in Thailand, Vietnam, Cambodia and, now, Indonesia.

The Chinese have also never reported any outbreak in Sichuan - among poultry or people. But outbreaks in Shantou, Hunan and Yunnan were not reported either.

However, we know these did occur.

A paper published in July in the journal Nature detailed the genomics of H5N1 isolated in samples taken in 2005 from Qinghai and Guangdong as well as Hunan and Yunnan.

Dr Guan Yi, a University of Hong Kong scientist, told the media that, soon after the Nature paper was published, the mainland authorities accused him of stealing state secrets.

So China considers H5N1 a state secret - the Qinghai isolates have been shown to be very virulent - perhaps because people have already been infected?

If so, we have much to fear.

The city of Ziyang where patients are dying lies close to Chengdu, the provincial capital which is 250km south-east of Qinghai.

Should human cases emerge among Chengdu's 10 million people - it has an international airport - bird flu could spread even faster.

China may not be alone in under-reporting H5N1.

In India, where pigeons died en masse on one occasion in 2004, the blood of poultry workers collected in 2002 shows antibodies to H5N1. Officially, though, India has no H5N1. This month's first human cases in Indonesia, with two deaths, may be linked to trips made to India and Hong Kong.

Alas, this stonewalling can kill as the H5N1 acquires more lethal genes - like Ebola genes.

Although it has never been officially seen outside Africa, the intrepid Boxun.com reported last April an Ebola outbreak in Shenzen, next to Hong Kong, which the authorities denied. Now, Boxun sources tell them that the Sichuan outbreak is the rapidly evolving Ebola SZ-77 strain which can infect birds, so it may be tied to bird flu at Qinghai.

Incredible? Pittsburgh-based genomics expert Henry Niman told The Straits Times he has noticed a gene in H5N1 'that is an exact match for an Ebola gene. So it is possible that a dual infection in birds or people may be leading to a new H5N1 - or a new Ebola virus.'

Yes, a swap between bird flu and ebola viruses can happen. Dr Niman said: 'They just need to be in the same host cell.'

Let's hope this has not really happened yet. Otherwise, we could all be in the same boat, a rapidly leaking one at that.