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Genotypes, Genotype 3 (GT3) in VA, Global
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Download the PDF here -
Mapping Diverse Global HCV Genotype Distribution- Europe/1b in Far East
http://www.natap.org/2014/HCV/022114_04.htm
VA
A total of 88,348 patients (79.9%) had HCV genotype 1, 13,077 (11.8%) genotype 2, 8,337 (7.5%) genotype 3, and 1,082 (0.9%) patients had genotype 4 infection. There were significant demographic and clinical differences among the HCV genotype groups (Table 1). Patients with genotype 3 were younger (mean age, 50.2 years, SD 6.4 years) whereas those with genotype 2 were older (mean age 52.7 years, SD 7.5 years) than patients with genotype 1 infection (mean age, 51.9 years, SD 6.6 years) (P<0.0001). Genotype 3 patients were more likely to have served in the post-Vietnam era (31.4%) compared to HCV genotype 1 (25.3%) and 2 patients (22.6%) (P<0.0001). Both genotype 2 and 3 patients were more likely to be white non-Hispanic compared to genotype 1 patients. HCV genotype 3 patients were less likely to have diabetes, HIV coinfection, and had lower BMI than genotype 1 patients. As expected, significantly more patients with HCV genotypes 2 and 3 received antiviral treatment and achieved SVR compared to genotype 1 patients. HCV genotype 4 patients were more likely to be Hispanics and diabetics than HCV genotype 1 patients.
A systematic reviewof hepatitis Cvirus epidemiology in Asia, Australia
and Egypt
India, Pakistan, Australia, Thailand - High rates GT3
In India and Pakistan genotype 3 predominates, which, because of the very large populations in these two countries, constitutes one of the largest concentrations of people infected with genotype 3 in the world. Middle Eastern countries such as Egypt, Saudi Arabia and Syria predominantly have genotype 4 infection, although genotype 3 can be found in other Middle Eastern countries such as Iraq and Iran, probably related to migration patterns in this area.
Thailand
Genotype distribution
An analysis of 45 samples collected in 2004 from four separate regions of Thailand showed genotype 3 as dominant: 1 [33.3%
with 1a (6.7%) and 1b (26.7%)], 2c (4.4%), 3 [53.3% with 3a (51.1%) and 3b (2.2%)] and 6 (8.9%) (305). Additional studies sampled blood donors and estimated genotype 3 at 44% of the infected population (318, 319). In contrast, a sample of 46 chronic liver disease patients found genotype 1 as most prevalent. Genotype 1 and its subtypes comprised 48% (320).
India
Genotype distribution
The most prevalent genotype was 3, with estimates ranging between 61.8 and 80.2% (101, 102, 104-106, 126-135). A study of 2118 patients across the country found genotypes 1 (31.2% with 1a/b = 92.4%, 1c = 7.6%), 2 (0.5%), 3 (61.8% with 3a/b = 94.9%, 3g/k = 5.1%), 4a/d (4.5%) and 6 (1.9%) (126). They also reported that genotype 3 was most prevalent in the Northern and Eastern regions, while in Western and Southern India the distributions of genotypes 3 and 1 were more even, with genotype 3 between 43 and 52% and genotype 1 between 43 and 48%. A study of 398 patients from North and Central regions also showed genotype 3 as the most common (80.2%), followed by genotype 1 (13.1%) (102). The presence of genotypes 4 and 6 in these populations could indicate a spread from Eastern Asia, where these genotypes are more prevalent.
Vietnam
Genotype distribution
The most common HCV genotypes in Vietnam were 1 and 6. There were a number of genotype studies (322, 322, 323, 326, 327). A study in 70 RNA-positive blood donors in Hanoi reported the following genotypes: 1 [47.1% with 1a (30.0%) and 1b (17.1%)], 3 [5.8% with 3a (2.9%) and 3b (2.9%)] and 6 [47.1% with 6a (37.1%), 6e (8.6%) and 6i (1.4%)] (328). Genotype 6 was reported to occur in South China as well as Vietnam, Laos, Thailand and Myanmar (328). In 79 HCV RNA-positive donors from Ho Chi Minh City and four HCV RNA-positive donors from Hanoi, genotype 1 was the predominant genotype (54.0%), composed of genotype 1a (27.0%), 1b (23.0%) and mixed genotype 1 (4%) (323). However, 41% of
the genotyped samples were not classifiable into genotypes 1, 2 or 3, and further analysis indicated the majority of the unknown samples were genotype 6a (19.3%) (327). This suggested a geographical distribution of HCV genotypes in Vietnam. Smaller studies reported genotype 1 as the predominant genotype, ranging from 42.8 to 75.0% (322, 326), with the majority typed as genotype 1a (23.8-50.0%), followed by 1b (23.8-25.0%).
Japan
Genotype distribution
There were a number of publications from 1993 to 2000, and almost all indicated genotype 1b as dominant (158, 159, 171, 187-189). In a 2000 study with 166 samples from an endemic area, the following genotypes were identified: 1b (63%), 2a (25%) and mixed/other (12%) (158). Other studies showed similar results, but further breakout of subtypes (187, 188). The only exception was a study by Kobayashi et al. (189), which showed no genotype 1, genotype 2 at 73.3% and genotype 3 at 18.2%. This study was limited to a single hospital located in Tokyo. Except for the latter study, all others showed very small percentages for genotypes 3 and 4.
Australia
Genotype distribution
The published studies were completed 1 year apart and all reported similar results (21, 25-27). A study of 425 patients from a single hospital population reported genotypes 1 (14%), 1a (15%), 1b (23%), 2 (9%), 3 (31%), 4 (5%), 6 (2%) and mixed (1%) (27). The results were consistent with other work conducted by a national reference laboratory (26), which also showed that genotype 3 was more prevalent in younger age cohorts (21-40 year olds), indicative of transmission via IDU, and that genotype 1b was identified more frequently among patients with transfusion-acquired HCV (26).
China
Genotype distribution
Genotype distributions were reported by studies published in 1994-2006 (55-58). A study of 139 HCV patients sampled from nine regions in China (56) reported genotypes 1 (67.6%), 2 (14.4%), 3 (4.3%), 6 (13%) and other (0.7%). Genotype 1b was the most prevalent at 66.2%, and genotype 2a showed a prevalence of 13.7%. Statistically significant geographical differences were observed, and genotype 6 was only observed in the South (56).
A more recent study from Hong Kong sampled 1055 IDUs and non-IDUs in 1998-2004. The non-IDU population showed a genotype 1b prevalence of 63.6%. Genotypes 2a and 3 had prevalence rates of 3.1 and 3.9%, respectively, and genotype 6a was found in 23.6% of participants. The IDU population showed statistically different genotype distributions, where genotype 6a was seen in 58.5% and 1b in 33.0% (55).
Pakistan
Genotype distribution
Genotype distribution information was derived from three studies, which agreed that genotype 3 is the most prevalent genotype (208, 225, 245). The largest study included 3351 individuals from across the county and found the following genotypes: 1 [11.5% with 1a (8.3%) and 1b (3.0%)], 2 [8.4% with 2a (7.5%) and 2b (0.8%)], 3 [67.5% with 3a (49.1%) and 3b (17.7%)] (208). The smaller studies estimate genotype 3 at higher rates of 81.0-86.7% (225, 245), potentially because of the sampling. Similarly, however, genotype 1 was the next most prevalent, showing near agreement among all studies.
Saudi Arabia
Genotype distribution
Genotype 4 is the most prevalent genotype, followed by genotype 1 (277-282). Among 561 consecutive genotypes performed in a single centre (NGHA) in 2006-2010, the following genotypes were identified: 1 (23.4%), 2 (3.2%), 3 (3.4%), 4 (60.9%) and mixed genotypes, mostly genotypes 4 and 1 (8.7%). Genotype 5 was rare and genotype 6 was nonexistent (I. Altraif et al., unpublished data).
Other studies found varying genotypes, where genotype 4 was found in 74% and genotype 1 in 14% (283, 284). In haemodialysis and chronic renal failure patients, infection with genotypes 1 and 4 was almost equally distributed (283, 284). In IDUs, however, genotype 1 was more prevalent (48%), with the majority genotype 1b (39%), followed by genotype 4 (36%) (283).
Egypt
Genotype distribution
Genotype 4 predominates in Egypt. There are a number of reports (96-98), and a study of 131 HCC and chronic hepatitis C patients found the following genotype distribution: 1 (6%), 3 (1%) and 4 (93% with 4a = 63%) (96).
Syria
Genotype distribution
Genotype 4 was the most common genotype. From a sample of 636 patients from eight medical centres throughout the country, the following genotypes were identified: 1 (28.5%), 2 (0.8%), 3 (1.8%), 4 (59.0%) and 5 (10.1%) (285). On the other hand, a small single-centre study (n = 37) found genotype 4 (30%) to be less common than genotype 1 (46%) (289).
Taiwan
Genotype distribution
A study of 418 chronic HCV patients at a tertiary referral hospital and another on 1164 patients from three hyper endemic areas found very similar genotype distribution with 1b and 2a being dominant: 1 [48% with 1a (2.6%), 1b (45.5%)], 2 [39.5% with 2a/c (30.9%), and 2b (6.9%)], 3a (1%), 4 (0.2%), 6 (0.5%) and mixed/other (10.0%) (301, 302). It was noted that genotype 1b increased with age, while genotype 2a decreased with age
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