Proses terjadinya keganasan flu babi

Pada umumnya zat kebal tubuh (antibodi) yang ditimbulkan karena imunisasi atau infeksi virus influenza secara alami dapat menangkal serangan infeksi virus yang kedua dan seterusnya. Prinsip serangan sistem kekebalan pada penyakit influenza tertuju pada hemagglutinin virus. Gen virus influenza ini mudah mengalami mutasi yang dapat membuat perubahan karakter virus. Sebagai hasil mutasi gen terjadilah perubahan komposisi asam amino hemaglutinin virus ini secara konstan, sehingga perlindungan penderita yang terinfeksi virus influenza menurun secara perlahan-lahan. Keadaan ini disebut antigenic drift. Perubahan yang perlahan-lahan ini tidak merubah kedudukan ikatan antibodi dengan antigen. Mutasi asam amino individual semacam itu tidak menimbulkan wabah. Sehingga hanya kehilangan kekebalan sebagian pada suatu populasi dan beberapa infeksi yang terjadi hanya menimimbulkan gejala ringan.

Tetapi jika seluruh bagian hemaglutinin baru terdapat di dalam virus, akan dapat menimbulkan wabah yang meluas ke seluruh dunia. Hal ini terjadi karena tidak ada lagi perlindungan kekebalan yang tersisa untuk melawan infeksi virus baru tersebut. Keadaan ini disebut antigenic shift. Pada suatu keadaan tertentu dapat terjadi dua strain virus influenza menginfeksi sebuah sel. Pertukaran segmen gen antara virus asal manusia dan virus asal unggas dapat terjadi dan akan menghasilkan virus reassortant baru.

Pertukaran partikel RNA terjadi pada proses pembentukan nucleocapsid virus baru. Sehingga diperoleh virus dengan selubung luar protein berasal dari suatu virus dengan partikel RNA baru yang berbeda dengan induknya. Virus ini bisa sangat berbahaya. Salah satu pandemik yang diyakini sebagai hasil reassortment antara influenza manusia dan burung adalah terjadi pada tahun 1918 dan menelan korban 20 juta orang meninggal.

Babi dinilai oleh para ahli sebagai tempat reassortment gen virus flu burung. Oleh karena itu memberikan hewan mati terinfeksi flu burung kepada babi dapat menimbulkan virus flu burung baru yang ganas. Untuk mencegah keadaan seperti ini maka dianjurkan agar ayam yang terinfeksi atau mati karena terinfeksi flu burung harus dimusnahkan dengan cara dikubur atau dibakar.

Virus flu dari manusia dapat menular ke babi dan virus flu burung dari unggas juga dapat menular ke babi. Pada tubuh babi kedua virus tersebut dapat bermutasi atau saling bertukar gen dan menjadi subtipe virus baru.

Pembentukan subtipe virus baru itu memungkinkan terjadinya penularan virus dari hewan ke manusia. Penularan dengan cara itu sangat mungkin terjadi apabila lokasi peternakan ayam, babi dan permukinan manusia berdekatan. Maka dari itu perlu diatur agar peternakan ayam harus terletak jauh dari peternakan babi untuk mencegah terjadinya reassortment gen virus flu burung dan flu manusia pada babi.

Sumber:
Infovet edisi 116, tahun 2004: Penanganan Flu Burung oleh Drh. Pudjiatmoko, Ph.D. Ilmuwan dari Masyarakat Ilmuwan dan Tekhnolog Indonesia (MITI)

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Six phases of swine flu pandemic

The WHO has six phases of pandemic alert to access the potential for new global flu outbreak.

Phase 1:
There are no viruses circulating in animals that have been reported to cause infections in humans.

Phase 2:
An animal flu virus has caused infections in human in the past and is considered to be a potential pandemic threat.

Phase 3:
An animal or mixed animal-human virus has caused occasional cases or small clusters of disease, but the virus does not spread easily.

Phase 4:
The new virus can cause sustained outbreaks and is adapting itself to human spread (April 28, 2009).

Phase 5:
The virus has spread into at least two countries and is causing even bigger outbreaks (April 30, 2009)

Phase 6:
Outbreaks in at least two regions of the world; the pandemic is under way.

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From fossil fuel to bioenergy

Biomass power from waste wood

MES group works comprehensively on biomass power plant from construction, operation and maintenance of the plant to supply control of fuel

Biomass power generation

This plant is to generate electricity firing fuel made from demolished house wood and house organic waste, etc. In Japan about 330 biomass generation plants are in operation at the end of October 2008.

Green Power Ichihara Co. Ltd. An MES’s subsidiary company, constructed biomass power plant in the premises of Chiba Works of MES aiming to mainly use demolished house wood together with refuse paper and plastic fuel (RPF) gathered from Tokyo metropolitan and its surrounding prefectures.

Power generation capacity of the plant is 49,900 kW and power transmission capacity is 43,800 kW, which are the largest scale in Japan as the biomass generation plant. The wood chip fuel and RPF are supplied by recycle Sources Company, established by MES and New Energy Supply Company, under supply control where temporary storage as necessary and timely supply of the fuel are made.

Approx. 350 thousand tons of CO2 (equivalent to about 100 thousand kl of crude oil) can be decreased in a year by this power plant.

The fuels for the biomass power plant

As mentioned above the fuels are recycled wood chips and RPF. The wood chips are made from demolished houses and wood remainder materials after lumbering by refining removing impurities. Other fuel used is RPF. It is the high-calorie solid fuel made from waste paper and plastics, which are difficult to be recycled to paper and plastic.

Biogas, electricity, heat source, liquid manure, etc. from human excreta, garbage, etc.

MES had been tackling the development of disposal plant for human excreta, sludge from the waste water treatment facility, household garbage, etc. for several decades, and has constructed many plants in the past. In the recent years in line with the enhancement of social consciousness for preservation of environment, such treatment facilities to be newly constructed are changing from mere treatment facility to the facility to the recycle such waste to valuable things as biogas, electricity, heat resource, fertilizer, etc.

One of such facility is recently constructed in Oki Town, Fukuoka Prefecture in western part of Japan. The facility named “Oki Recycling Center Kururun” was born as a Framework for Biomass Town, availing subsidy of the Japanese Ministry of Agriculture, Forestry and Fisheries. In this facility human excreta, sludge from waste water treatment and household garbage are mixed and fermented to make liquid manure, which is recycled to farmland. Further, biogas made in the process of fermentation is utilized to generate power to be used for the electricity required for operation of the facility.

Biogas, electricity, heat source, manure from garbage

Another plant MES would like to introduce is the waste treatment facility named “Recyclean” constructed in Nakasorachi, Hokkaido, located in the northern part of Japan. This plant is largest class garbage disposal facility in Japan and can treat 55 tons (nominal capacity) of garbage gathered from 40 thousand households and offices in the Nakasorachi area in a day. The garbage is fermented to biogas to be used for power generation and as boiler fuel. The electricity made is used for operation of the facility and the surplus electricity is sold to electricity Company. Further, heat produced by generator and boiler is used to heat methane fermentation tank and road heating. In addition, sludge after methane fermentation can be utilized as the high quality farmyard manure, since the gathered garbage in collecting bags is made to pure garbage by removing the collecting bags and metal materials in the preliminary treatment process.

Source: MES Bulletin 64, 2009

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