Mishnah Zavim 5:1: If one [who is clean] touches a zav or if a zav touches him, [or] if one moves a zav, or if a zav moves him, he renders unclean food, drink and utensils that can be rinsed [immersed in a mikva and thereby made clean] through touch, but not through carryinng. Rabbi Yehoshua stated [the following] general principle, Anyone that renders garments unclean while in contact [with the source of his uncleanliness], renders unclean food and liquids to become a first level uncleanliness and the hands to become a second level of uncleanliness, and does not render unclean people or earthenware vessels. After he has separated from the source of his uncleanliness, he renders unclean liquids to become a first level uncleanliness, and food and hands to become a second level of uncleanliness, and he does nor tender garments unclean.

הַנּוֹגֵעַ בַּזָּב אוֹ שֶׁהַזָּב נוֹגֵע בּוֹ, הַמַּסִּיט אֶת הַזָּב אוֹ שֶׁהַזָּב מַסִּיטוֹ, מְטַמֵּא אֳכָלִים וּמַשְׁקִים וּכְלֵי שֶׁטֶף בְּמַגָּע, אֲבָל לֹא בְמַשָּׂא. כְּלָל אָמַר רַבִּי יְהוֹשֻׁעַ, כָּל הַמְטַמֵּא בְגָדִים בִּשְׁעַת מַגָּעוֹ, מְטַמֵּא אֳכָלִים וּמַשְׁקִין לִהְיוֹת תְּחִלָּה, וְהַיָּדַיִם לִהְיוֹת שְׁנִיּוֹת, וְאֵינוֹ מְטַמֵּא לֹא אָדָם וְלֹא כְלֵי חֶרֶס. לְאַחַר פְּרִישָׁתוֹ מִמְּטַמְּאָיו, מְטַמֵּא מַשְׁקִין לִהְיוֹת תְּחִלָּה, וְהָאֳכָלִין וְהַיָּדַיִם לִהְיוֹת שְׁנִיּוֹת, וְאֵינוֹ מְטַמֵּא בְגָדִים:

Mishnah Zavim 5:2: Another general rule they said, Anything that is carried above a zav [even though there is no contact] becomes unclean and all things above which he [the zav] is carried is clean except objects on which he can sit or lie upon and a person. How so [does this law apply]? [If] the finger of a zav was under a layer of stones and one [a person] that is clean is [sitting] above, he renders unclean at two [levels] and renders unfit [terumah] at one [level more]. If he separated himself [from the source of unclenaliness], he renders unclean at one [level] and renders unfit [terumah] at one [level more]. If the unclean one was above, and the clean one below, he renders unclean at two [levels], and disqualifies [terumah] at one [level more]. If he separated himself [from the source of uncleanness], he renderds unclean at one [level] and renders unfit [terumah] at one [level more]. [If] food, liquids or objects on which he can sit or lie upon or madaf [other articles] were above [the zav], he renders unclean at two [levels], and disqualifies [terumah] at one [level more]. If he separated himself [from the source of uncleanness], he renderds unclean at one [level] and renders unfit [terumah] at one [level more]. If objects on which he can sit or lie upon were below [the zav], he renders unclean at two [levels], and disqualifies [terumah] at one [level more]. If he separated himself [from the source of uncleanness], he renderds unclean at two [levels] and renders unfit [terumah] at one [level more]. If food, liquids and a madaf are below they are clean.

וְעוֹד כְּלָל אַחֵר אָמְרוּ. כֹּל הַנִּשָּׂא עַל גַּבֵּי הַזָּב, טָמֵא. וְכֹל שֶׁהַזָּב נִשָּׂא עָלָיו, טָהוֹר, חוּץ מִן הָרָאוּי לְמִשְׁכָּב וּלְמוֹשָׁב וְהָאָדָם. כֵּיצַד. אֶצְבָּעוֹ שֶׁל זָב תַּחַת הַנִּדְבָּךְ, הַטָּהוֹר מִלְמַעְלָן, מְטַמֵּא שְׁנַיִם וּפוֹסֵל אֶחָד. פֵּרַשׁ, מְטַמֵּא אֶחָד וּפוֹסֵל אֶחָד. הַטָּמֵא מִלְמַעְלָן וְהַטָּהוֹר מִלְּמַטָּן, מְטַמֵּא שְׁנַיִם וּפוֹסֵל אֶחָד. פֵּרַשׁ, מְטַמֵא אֶחָד וּפוֹסֵל אֶחָד. הָאֳכָלִין וְהַמַּשְׁקִין, הַמִּשְׁכָּב, וְהַמּוֹשָׁב וְהַמַּדָּף מִלְמַעְלָן, מְטַמְּאִין שְׁנַיִם וּפוֹסְלִין אֶחָד. פֵּרְשׁוּ, מְטַמְּאִין אֶחָד וּפוֹסְלִין אֶחָד. וְהַמִּשְׁכָּב וְהַמּוֹשָׁב מִלְּמַטָּן, מְטַמְּאִין שְׁנַיִם וּפוֹסְלִין אֶחָד. פֵּרְשׁוּ, מְטַמְּאִין שְׁנַיִם וּפוֹסְלִין אֶחָד. הָאֳכָלִין וְהַמַּשְׁקִין וְהַמַּדָּף מִלְּמַטָּן, טְהוֹרִין: