Condom poster: What should 爪 in ...因爪安全性行为感染艾滋病 actually be? And why is 经 in 预防艾滋病经性传播? Question:  What should 爪 in 天津市平均每周都有１名学生因爪安全性行为感染艾滋病 actually be?  And why is 经 in 预防艾滋病经性传播?
Why I ask: this poster has appeared in some campus bathrooms (in the women's ones, at least):


(large image)

Zooming in, the first part is:



I transcribe and translate this to:

天津市每发现１０例ＨＩＶ感染者
其中就有７例是通过男男同性性行为传播
天津市平均每周都有１名学生因爪安全性行为感染艾滋病
In Tianjin, in every 10 cases of discovered HIV infection
among these are 7 cases spread through male-male same-sex sexual activity
The Tianjin average, every week has 1 student, because of [爪 (?)] unsafe sex, is infected with aids

I don't think 爪 (=claw) is correct, but I couldn't find the correct character.  (My phone suggests , but it doesn't appear in dictionaries.)
And I transcribe and translate what the condom says:


预防艾滋病经性传播
从坚持正确使用安全套开始
To prevent aids [经 (?)] and sexually transmitted diseases
start with insisting on proper use of condoms

I'm not sure what 经 (YouDao, dict.cn) is doing here.  I don't see a relevant definition.  Is it yet another word for &quot;and&quot;?  Or maybe it means &quot;and other&quot;, or &quot;along with&quot;.
It is 不安全性行为 (unsafe sex) , not 爪安全性行为

经 means 'through'

性 means 'sex'

预防艾滋病(经)性传播 = prevent aids spread (through) sex

A more clear phrasing might help new learners understand better - 预防艾滋病经(由)性(愛/交)传播

经由 = 'through'

性愛 = 'love making'

性交 = 'sexual intercourse'